LIBRARY 

OF  THK 

UNIVERSITY  OF  CALIFORNIA. 

Class 


A  GENERAL  CONSIDERATION 


...  OF  THE  .  .  . 


Utilization  of  Wood  Waste 


by  Distillation 


A  General  Consideration  of  the  Industry  of 
Wood  Distilling,  including  a  description  of  the 
apparatus  used  and  the  principles  involved 


...ALSO... 


METHODS    OF    CHEMICAL    CONTROL 
AND    DISPOSAL    OF    THE    PRODUCTS 


...BY... 

WALTER  B.  HARPER,  M.  S. 


First  Edition 
Illustrated  by  Seventy-four  Engravings 


1  IRA.  j|>^ 

OF  THE 


UNIVERSITY   | 

OF  / 


ST.  LOUIS,  MO.. 
JOURNAL  OF  COMMERCE  COMPANY 

PUBLISHERS 
ST.  LOUIS  LUMBERMAN 


COPYRIGHT,    1907, 

BY 
JOURNAL  OF  COMMERCE  CO. 

ST.  LOUIS,  MO. 


CONTENTS 


CHAPTER  I.  Page 

Introduction 17 

CHAPTER  II. 

Historical  Connection    18-19 

CHAPTER  III. 
Principles  of  Distillation 20-25 

CHAPTER  IV. 

Apparatus  Necessary  for  Destructive  Distillation 26-40 

Swedish  Oven / .-...' 27 

Vertical  Retort    30 

Charcoal  Coolers 31 

Condensers    33 

Box  Condenser 34 

Worm 34-35 

Counter  Current  Pipe  Cooler 36 

Tubular  Condenser  37 

Receivers  and  Storage  Tanks 40 

CHAPTER  V. 

Refining  Methods    41-49 

Turpentine   Stills    41 

Tar  Stills  44 

Wood  Oil  Stills   45 

Still  Heads 45 

Alcohol  Stills  and  Acetate  Pans 47 

Condensers 47 

Storage  Tanks 48 

Condensing  Water 48. 

Shipping  and  Packages 49 

CHAPTER  VI. 

Special  Combinations  of  Apparatus  as  Used  in  Modern  Plants 50-101 

Steam  Processes  51 

Steam  and  Destructive  Distillation  and  Destructive  Distillation  Plants.  57 

Horizontal  Retorts 58 

Vertical  Retorts 69 

Special  Retorts  and   Processes . .  83 

Rotary  Processes 84 

Movable  Retorts   93 

Conveyor  Processes   96 

Pierce  Process  -. 100 

Patents  100-101 

CHAPTER  VII. 

The  Execution  of  the  Processes  of  Wood  Distillation 102-109 

The  Steam  Process   102 

Steam  and  Destructive  Distillation  104 

Special  Process  107 

Wood  Gas  Making   107 

CHAPTER  VIII. 

Refining    Processes  . . . '. 110-112 

Mallonee's    Apparatus    110 

Gilmer's  Refining  Process  Ill 

Heber's  Process  .                       112 


CONTENTS 


CHAPTER  IX.  Page 

General  Consideration  for  the  Establishment  of  a  Plant 113-119 

Market  Conditions 117 

Steam    Plant 118 

CHAPTER  X. 

Composition  of  Wood  and  Products  of  Distillation 120-133 

Gases    121 

Wood  Oil,  and  Tar 121 

Wood  Vinegar  and  Wood  Alcohol 122 

Residue    122 

Turpentine    123 

Pinene    124 

Dipentene    125 

Sylvestrene     125 

Pine    Oil    126 

Resin     Oil     126 

Rosin 127 

Rosin  Spirit    127 

Rosin    Oil    128 

Tar    129 

Pitch 130 

Pyroligneous  Acid  130 

Acetone    • 131 

Calcium  Acetate   132 

Charcoal 132 

CHAPTER  XI. 

Yields  and  Disposals  of  Products   134-138 

CHAPTER  XII. 

Chemical   Tests  and   Combinations    139-147 

Combinations   or  derivatives    140 

Wood   Residues    143 

CHAPTER  XIII. 

Chemical  Control  of  Plant  for  the  Distillation  of  Wood  148-156 

Measurements 148 

Sampling    149 

Standardizing    Apparatus    149 

Analysis 150 

Acetates   153 

Wood     153 

Moisture     153 

Creosote     155 

Acetone    156 

Bibliography 157 


ILLUSTRATIONS 


Page 

Fig.     1,       Water  Still   20 

Fig.     2,       Retort  and  Worm  21 

Fig.     3,       Italian  Charcoal  Kiln 21 

Fig.     4,       Horizontal  Charcoal  Kiln  22 

Fig.     5,       Tar  Kilns 23 

Fig.     6,       Bee  Hive  Oven    24 

Fig.     7,       Rectangular  Brick  Kiln 25 

Fig.     8,       Swedish  Oven 27 

Fig.     9,       Horizontal  Retort  29 

Fig.  10,       Vertical  Retort 30 

Fig.  11,       Connections    31 

Fig.  12-A,  Separator 32 

Fig.  12-B,  Separator 32 

Fig.  12-C,  Separator  33 

Fig.  13,      Box  Condenser    35 

Fig.  14,      Double  Pipe  Counter  Current  Condenser 36 

Fig.  15,       Connection  of  Counter  Current  Pipe  Cooler 37 

Fig.  1C,       Tubular  Condenser 38 

Fig.  17,       750  Gallon  Steam  Heated  Turpentine  Refining  Still 41 

Fig.  18,       Still  Heads   45 

Fig.  19,       Hege's  Patent  Head 46 

Fig.  20,  Shipping  Turpentine  and  Tar  at  a  Steam  and  Destructive  Dis- 
tillation Plant 49 

Fig.  21,      Krug's  Patent  (Plan)    52 

Fig.  22,      Hoskins   Patent 53 

Fig.  23,       Mallonee's  Process  54 

Fig.  24,       Hirsch's  Process 55 

Fig.  25,       Gardner's  Process 56 

Fig.  26,       James'  Process    56 

Fig.  27,       McMillan's  Process    57 

Fig.  28,      Wheeler's  Process 58 

Fig.  29,       Messau's  Process    59 

Fig.  30,       Hansen  &  Smith  Process   60 

Fig.  31,       Koch's   Process 61 

Fig.  32,      Badgley's  Process  61 

Fig.  33,       Inderleid's  Process  62 

Fig.  34,       Chapman's   Process    62 

Fig.  35,       Gilmer's    Process    63 

Fig.  36,       Broughton's  Process 64 

Fig.  37,       Mallonee's  Process  (Fig.  1) 65 

Mallonee's  Process   (Fig.  2 66 

Mallonee's  Process   (Fig.  3) 67 

Mallonee's  Process  (Fig.  4) 67 

Fig.  38,       Palmer's  Process 68 

Fig.  39,      Hessel's  Process   69 

Fig.  40,       Roake's   Process 69 

Fig.  41,       Bilfinger's    Process 70-71 

Fig.  42,       Palmer's    Process 72 

Fig.  43,       Douglas's  Process 73 

Fig.  44,       Clark  &  Harris  Process  74 

Fig.  45,       Sibbitt  &  McLean 75 

Fig.  46,       Friis  Process    76 

Fig.  47,       Ross  &  Edwards  Process 77 

Fig.  48,       Mathieu's  Process 77 

Fig.  49,      Jewett  Process 78 

Fig.  50,      Fiveash  Process 78 

Fig.  51,      Williams's    Process 79 

Fig.  52,       Snyder's   Process    79 

Fig.  53,      Copilovich  Process 80 

Fig.  54,      Denny's  Process   81 


ILLUSTRATIONS 


Page 

Fig.  55-A,  The  Krug  Steam  Process — Showing  Retorts 82 

Fig.  55-B,  The  Krug  Steam  Process,  Showing  Condensers 82 

Fig.  56,  Steam  and  Destructive  Process,  Using  Coolers  and  Cars 83 

Fig.  57,  Berry's  Process   84 

Fig.  58,  Spurrier's  Process 85 

Fig.  59,  Larsen's  Process  86 

Fig.  60,  Halliday's  Apparatus  87 

Fig.  61,  Viola  Process  88 

Fig.  62,  Harper's   Process    89 

Fig.  63,  Fleming's  Process 90 

Fig.  64,  Jackson's  Process  91 

Fig.  65,  Handford's  Process   y2 

Fig.  66,  Smith's  Process  (Fig.  3  and  Fig.  5) 93 

Fig.  67,  Davis'    Process    94 

Fig.  68,  Weed's    Process     95 

Fig.  69,  Hale  &  Kursteiner  Process 96 

Fig.  70,  Dobson's  Process    < 97 

Fig.  71,  Kerr's  Process 98 

Fig.  72,  German  Destructive  Distillation  Plant   105 

Fig.  73,  Mallonee's  Refining  Process 110 

Fig.  74,  Gilmer's  Refining  Process  Ill 


OF   THE 

UNIVERSITY 

OF 


PREFACE 

The  lack  of  literature  on  the  subject  of  wood  distillation,  particu- 
larly that  which  relates  to  the  treatment  of  resinous  woods,  led  the  au- 
thor to  believe  that  a  description  of  the  various  processes  that  have  been 
used  or  suggested  to  accomplish  this  purpose  might  be  interesting  and 
acceptable  to  many. 

In  the  pine  wood  industry  so  much  money  has  been  wasted  trying  to 
carry  out  successfully  the  plans  of  over-enthusiastic  promoters  that  it  is 
well  to  direct  along  sane  lines  of  investment  any  further  capital  that  may 
be  advanced  for  distillation  processes.  Great  and  wonderful  results  have 
been  promised  by  promoters  and  in  most  cases  the  processes  tried  did  not 
even  yield  a  small  profit.  This  bad  result  has  been  caused  chiefly  by  the 
fact  that  those  who  have  experimented  with  the  various  processes  on  the 
small  scale  have  made  erroneous  deductions  from  the  results  obtained. 
Usually  some  feature  that  is  essential  to  success  has  been  overlooked  and 
when  the  process  is  started  on  a  large  scale  this  feature  is  brought  out  so 
prominently  that  it  cannot  be  successfully  overcome  and  the  plant  fails. 
The  greatest  mistake  is  usually  the  estimation  of  the  cost  and  quantity 
of  the  particular  grade  of  wood  with  which  the  experiment  was  made. 
It  usually  develops  that  a  sufficient  quantity  of  wood  of  the  right  qual- 
ity cannot  be  obtained.  Many  of  these  essential  conditions  for  success 
are  pointed  out  in  the  text. 

The  lumbermen  should  be  the  most  interested  as  they  control  the 
forests.  The  great  inducement  to  lumbermen  to  enter  the  business  is  to 


PREFACE 

dispose  of  the  vast  quantity  of  refuse  incident  to  the  milling  operations. 
The  advisability  of  treating  refuse  will  depend  upon  the  quantity  and 
its  use  for  fuel.  With  the  use  of  band  mills  and  lath  mills,  the  amount 
of  refuse  is  getting  to  be  so  small  that  it  is  hardly  sufficient  to  supply 

enough  fuel  to  furnish  the  power  for  the  mill.    All  distilling  processes 

/ 
take  considerable  fuel,  consequently  it  is  only  at  those  mills  where  the 

refuse  has  no  value  as  fuel  that  it  would  pay  to  install  a  distilling  appa- 
ll 

ratus.  The  discussion  of  these  features  is  brought  out  in  the  book. 

In  the  forest  no  successful  method  has  been  discovered  to  utilize  pine 
or  fir  wood,  taking  the  wood  as  it  comes  without  selection  and  only  such 
a  process  could  be  called  a  success  economically.  It  is  to  be  hoped  that 
rotary  processes  may  achieve  that  end,  but  the  outlook  is  not  promising. 

It  has  been  the  author's  intention  to  write  this  book  in  such  a  man- 
ner that  the  different  phases  of  the  subject  might  be  touched  upon  and 
easily  comprehended  by  an  unscientific  person.  With  the  information 
herein  obtained  it  might  be  possible  for  him,  if  suitably  located,  to  estab- 
lish a  distilling  plant  on  a  sound  basis.  On  the  other  hand,  this  infor- 
mation may  save  some  parties  from  a  loss  in  a  contemplated  investment. 
Furthermore  the  book  ought  to  act  as  a  stimulus  to  those  who  are  al- 
ready engaged  in  the  industry. 

Most  of  the  credit  for  the  success  of  the  book  is  due  to  Mr.  W.  E. 
Barns  on  account  of  his  interest  in  the  matter  and  the  expense  incurred. 

A  great  deal  of  information  on  the  subject  has  been  taken  from  the 
articles  contained  in  the  columns  of  the  periodicals  given  in  the  append- 


PREFACE 

ed  list.  The  purpose  of  the  author  has  been  to  give  the  opinions  of  others 
prominence,  when  in  accord  with  facts.  More  explicit  information  relat- 
ing to  these  articles  would  probably  be  acceptable,  but  in  many  cases 
the  author  had  only  clippings  without  date. 

The  author  expresses  his  thanks  to  Dr.  C.  E.  Coates  of  the  Louisiana 
State  University,  for  the  use  of  his  library,  from  which  a  great  deal  of 
the  chemical  information  herein  contained  has  been  derived. 

The  arrangement  of  the  contents  might  have  been  improved  by  com- 
bining all  the  information  concerning  a  certain  product  under  one 
head.  However,  the  information  required  can  in  most  cases  be  easily 
found  by  consulting  the  index  and  table  of  contents. 

WALTER  B.  HARPER. 
Laboratory  of  the  La.  State  University. 

BATON  ROUGE,  April,  1907. 


OF  THE 

UNIVERSITY 

OF 


THE  UTILIZATION  OF  WOOD  WASTE 
BY  DISTILLATION. 


CHAPTER  I. 

INTRODUCTION. 


In  the  discussion  of  this  subject  the  chief  wood 
that  will  be  considered  is  the  long  leaf  yellow  pine 
or  Georgia  pine,  although  some  reference  will  b" 
made  to  other  kinds  of  wood. 

The  pine  contains  so  much  more  gum  and  resin 
that  it  offers  more  opportunity  for  successful  dis- 
tillation than  those  kinds  of  woods  which  contain 
few  of  these  substances.  On  account  of  the  abund- 
ance of  raw  material  any  successful  method  of 
using  the  vast  quantity  of  waste  pine  would  be  of 
great  importance  as  an  aid  to  the  material  welfare 
of  the  nation,  and  particularly  to  the  South.  The 
importance  of  this  problem  has  now  been  partly 
realized  by  a  large  number  of  individuals.  Some 
lumber  companies  in  the  South  have  already  made 
investigation  of  the  problem,  but  as  yet  none  have 
decided  fully  what  is  the  best  method  of  utilization. 

Distillation  of  the  wood  in  closed  vessels,  al- 
though of  very  ancient  origin,  has  been  brought 
forward  as  a  new  means  of  practically  disposing 


of  this  waste  product.  The  increasing  demand  and 
consequently  increasing  price  of  spirits  of  tur- 
pentine have  led  manufacturers  to  seek  some  sub- 
stitute. As  an  oil  closely  resembling  turpentine  can 
be  obtained  from  pine  wood,  and  even  fallen  and 
dead  pine  by  distillation  by  heating  with  steam 
or  direct  heat,  this  method  has  the  double  advantage 
to  the  country  of  supplying  a  substitute  for  a  com- 
modity, the  supply  of  which  is  evidently  failing  and 
at  the  same  time  utilizing  a  material  that  has  been 
almost  worthless  heretofore.  We  give  a  description 
then  of  some  of  the  attempts  that  have  been  made 
to  produce  a  successful  process  of  distillation.  A 
great  deal  has  been  done,  but  there  are  many  points 
to  be  worked  up  before  a  complete  utilization  can 
be  obtained  by  this  means.  It  is  almost  impos- 
sible to  calculate  the  amount  of  raw  material  ob- 
tainable for  this  purpose,  but  in  the  South  there 
are  fully  1,000,000  cords  that  are  annually  going 
to  waste  either  as  saw  dust  or  as  fallen  timber. 


CHAPTER  II. 

HISTORICAL  CONNECTION. 


Probably  the  ancients  noticed  the  fact  that  is 
so  apparent  to  all  who  have  made  wood  fires  that 
wood  chars  on  heating  to  a  black  coal.  There  then 
was  noticed  that  a  slow  fire  left  more  coal  when  it 
went  out;  after  this  in  attempts  to  smother  fires 
with  dirt  larger  quantities  of  charcoal  were  pro- 
duced, thus  leading  to  the  method  that  is  even 
now  prevalent  of  making  charcoal  by  smothering 
lighted  piles  of  wood  with  earth.  We  have  charcoal 
produced  in  the  South  today  by  stacking  wood 
and  covering  it  with  earth  and  igniting  the  wood 
at  the  bottom  of  the  pile.  This  method  of  treating 
wood  sufficed  to  attain  the  object  intended — that 
of  producing  charcoal.  That  the  vapors  and  gases 
produced  were  of  any  particular  value,  except  per- 
liaps  to  smoke  meat,  was  not  known  until  a 
much  later  date.  Glauber  in  Miraculum  Mundi, 
1658,  noticed  the  presence  of  pyroligneous  acid  in 
the  cooled  vapors,  and  Thenard  in  1802  showed  that 
this  acetic  acid,  or  pyroligneous  acid,  was  the  same 
.as  that  made  from  alcohol ;  but  it  was  not  until  the 
\discovery  of  the  presence  of  methyl  alcohol  by 
Taylor,  1812,  that  much  attention  was  given  to  the 
recovery  of  the  vapors.  We  find,  though,  that  M. 
Philip  Lebon  in  1799  made  use  of  the  gas.  and  ir. 
1801  he  lighted  his  house  with  gas  from  wood.  The 
gas  was  of  low  candle  power  as  then  produced,  but 
Pettenkofer  in  1849  showed  that  by  rapid  heating  of 
the  wood  a  much  more  luminous  gas  was  formed, 
and  this  gas  was  used  for  a  time  in  some  of  the 
old  German  cities. 

A  great  many  researches  on  the  destructive  dis- 
tillation of  wood  have  been  made  by  Violette,  Vin- 
cent, Stolze  and  others.  As  a  result  of  these  ir. 
vestigations  it  has  been  generally  observed  that 
lor  the  production  of  gas  and  charcoal  chiefly  the 
•distillation  should  be  performed  quickly  in  small 
apparatus  as  this  affords  means  of  quickly  heat- 
ing the  wood;  but  for  the  production  of  oils  and 
acetic  acid  large  retorts  heated  slowly  are  better. 


That  the  method  of  firing  influenced  the  quantity 
and  nature  of  the  distillate  is  shown  by  the  fol- 
lowing table: 


Wood 
100  Parts. 


J.UV     JTcLL  U3. 

•33 

5  a 

li 

<H 

2  -a  »i 
till 

&£& 

||| 

o 
cti  >> 

65 

S  <n 

0  QJ 
«  03 

£  <s 

Pa 

Hornbeam  — 

Slow   

52.40 

4.75 

47.68 

6.43 

25.37 

22.23 

Fast    

48.52 

5.55 

42.97 

5.23 

20.47 

31.01 

Birch- 

Slow   

51.05 

5.46 

45.59 

5.63 

29.64 

19.71 

Fast    

42.98 

3.24 

39.74 

4.43 

21.46 

35.56 

Beech— 

Slow   

51.65 

5.85 

45.80 

5.21 

26.69 

21.66 

Fast   

44.35 

4.90 

39.45 

3.86 

21.90 

33.75 

Oak- 

Slow  

48.15 

3.70 

44.45 

4.08 

34.68 

17.17 

Fast    

.45.24 

3.20 

42.04 

3.44 

27.73 

27.03 

Larch  —  • 

Slow,  

.51.61 

9.30 

42.31 

2.69 

26.74 

21.65 

Fast    

43.77 

5.58 

38.19 

2.06 

24.06 

32.17 

Spruce  — 

Slow   

.46.92 

5.93 

40.99 

2.30 

34.30 

18.7S 

Fast    

.46.35 

6.20 

40.15 

1.78 

24.24 

29.41 

The  above  is  from  the  tables  given  by  Prof. 
Fisher  in  his  Chemical  Technology.  The  slow  dis- 
tillation represents  starting  with  wood  in  a  cold 
retort  and  heating  slowly  for  six  hours,  and  the 
fast  distillation  represents  results  obtained  by  plac- 
ing the  wood  in  glowing  retorts  and  maintaining 
the  temperature  for  three  hours.  This  table  will 
be  of  some  service  to  a  distiller  wishing  to  know 
how  he  has  been  firing,  as  it  is  only  necessary  to 
compare  the  results  obtained  to  get  a  working 
idea. 

Sftolze's  table  shows  the  following  results  ob- 
tained by  careful  carbonization: 


100  Lbs. 


Birch     44.9 

Beech    44 

Hornbeam    42.5 

Oak    43 

Fir    .  ...42.3 


5  o  c  o 

EH£ 

6£ 

IS 

8.9 

.  8.6 

24.4 

9.8 

8.6 

9.5 

24.6 

It7.8 

7.6 

11.1 

23.9 

10 

7.7 

9.1 

26.1 

10 

4.2 

11.9 

26.6 

12.5 

THE    UTILIZATION    OF    WOOD     WASTE    BY    DISTILLATION, 


19 


And  Assmus  on  a  manufacturing  scale  shows  as 
follows: 


•a,; 


100  L 

Birch 
Birch 

<_                    IB     « 
bs.           ^J    -j 

Is"  - 

t>  d 
!>  be    0 

46 

;      o  i' 

-  "^^c 

2g3(S 

5.2 

•^  Acetic 
hydride 

,M 

d 
8 

co  Charco 
&  Pounds 

m 
W" 

60 

1.2 

• 

93  f 
•C™ 

4.5 

bark  — 

1st 

extract.  22 

0.6 

0.4 

30 

18.5 

21.6 

3 

Birch 

bark  — 

2nd 
Oak 
Fir    , 
Pine 

extract.  20 
42 

0.7 
6.0 
3.2 
3.0 

0.5 
4.5 
2.4 
2.3 

20 
8.8 
10.5 
9.5 

22 
27.5 
22 
22.6 

12 
0.8 
1.3 
0.6 

4.7 
3.3 
5.7 
3.5 

42 

.    44.5 

A  noticeable  feature  is  the  small  percentage  of 
acetic  anhydride  in  the  wood  vinegar  yielded  by 
the  pine  and  fir;  also  in  Stolze's  table  the  large 
amount  of  gas  yielded  by  fir.  These  features  of  the 
distillation  of  these  woods  explain  why  distillers 
of  yellow  pine  do  not  try  to  save  the  pyroligneous 
acid  or  wood  vinegar. 

These  are  some  of  the  results  obtained  in  Euro-- 
~pean  experiments  and  practice.  We  are  inter- 
ested to  know  of  early  American  attempts  to  utilize 
wood  so  that  we  may  obtain  the  benefit  of  Ameri- 
can experience.  The  manufacture  of  pyroligneous 
acid  was  begun  in  the  United  States  by  James 
Ward  in  1830  at  North  Adams,  Mass.  The  man- 
ufacture of  acetate  of  lime  and  methyl  alcohol  was 
started  in  the  United  States  by  James  A.  Emmons 
snd  A.  S.  Saxon  in  Crawford  county,  Pa.,  and  in 
"1374  George  C.  Edwards  established  the  Burcey 


Chemical  Works  at  Binghamton,  New  York,  to  re- 
fine the  crude  wood  spirit  produced  by  the  various 
acetate  manufacturers.  In  1876  Dr.  H.  M.  Pierce 
obtained  a  series  of  United  States  patents  for  in- 
ventions which  he  was  to  apply  to  the  recovery 
of  the  smoke  from  charcoal  kilns  in  Michigan. 
According  to  the  census  of  1900  in  the  Digest  of 
Patents  Relating  to  Chemical  Industries,  the  name 
of  M.  A.  LeBrun  Virloy  is  found  as  having  ob- 
tained a  patent  in  1863  for  a  special  furnace  for 
carbonizing  organic  matter.  The  next  one,  granted 
to  A.  H.  Emory  in  1865,  shows  that  turpentine  had 
been  extracted  from  pine  wood  before  this  time. 
Several  other  patents  after  this  mention  the  dis- 
tillation of  wood.  In  1872  a  patent  was  granted  to 
J.  D.  Stanley,  which  is  of  especial  interest,  as  he 
established  a  plant  at  Wilmington,  N.  C.,  which, 
although  it  proved  a  failure,  owing  to  lack  of  suf- 
ficient financial  backing  and  probably  other  causes, 
was  transferred  in  1878  to  the  Spiritine  Chemical 
Co.,  who  have  continued  it  with  more  or  less  suc- 
cess until  the  present  time.  Since  then  numerous 
processes  have  been  promoted,  mostly  copied  from 
German  or  French  methods,  and  each  year  adds 
new  patents  to  the  already  large  list.  A  descrip- 
tion of  some  of  these  will  be  given  later  as  a  great 
many  have  some  one  little  point  either  overlooked 
or  not  mentioned  by  the  others:  but  first  we  must 
take  up  the  general  consideration  of  distillation  in 
order  to  understand  more  fully  the  principles  upon 
which  they  are  based. 


CHAPTER  III. 

PRINCIPLES  OF  DISTILLATION. 


Distillation  comprises  that  process  which  consists 
in  heating  substances  in  closed  vessels  with  the  in- 
tention of  converting  the  substance  into  vapors  and 
of  condensing  these  vapors.  Sometimes  an  in- 
destructible  substance  is  left  as  a  residue  which 
is  not  further  acted  upon  by  the  degree  of  heat 
used.  Sometimes  the  vapors  are  composed  of  dif- 
•ferent  substances  than  the  original,  and  at  other 
times  when  the  original  substance  is  composed  of 
•a  mixture  of  materials,  the  vapors  of  each  separate 
^material  have  a  tendency  to  come  off  by  them- 
selves or  with  other  bodies  of  similar  physical 
properties. 

In  all  cases  of  distillation  we  find  that  the  vapora 
formed  occupy  a  great  deal  more  space  than  when 
the  substance  is  in  the  solid  or  liquid  state.  This 
is  well  exemplified  in  the  case  of  water  that  is 
turned  into  steam  or  water  vapor;  the  space  being 
nearly  seventeen  hundred  times  as  great  when  not 
compressed.  Generally  vapors  are  compared  with 
the  solid  or  liquids  in  the  ratio  of  1,00  J  to  1.  In  de- 
signing distilling  apparatus  this  point  must  be 
taken  into  consideration. 

The  object  of  distillation  is  to  separate  one  sub- 
stance from  another;  consequently  it  is  a  method 
of  purification.  Generally  in  the  case  of  liquids  the 
substances  distill  without  decomposition,  although 
not.  always  so.  Sometimes  to  prevent  decomposi- 
tion it  is  necessary  to  distill  under  a  vacuum.  When- 
ever the  material  distilling  is  overheated  decompo- 
sition generally  ensues.  In  the  case  of  solid  sub- 
stances great  difficulty  is  experienced  in  distilling 
them  without  decomposition.  It  is  only  those  sub- 
stances that  are  easily  melted,  or  are  of  an  ele- 
mentary or  mineral  nature  that  can  be  so  distilled. 
With  organic  substances  decomposition  generally  oc- 
curs to  a  more  or  less  extent. 

Whenever  this  decomposition  takes  place  it  is 
usually  called  destructive  distillation.  The  result- 
ing condensed  vapors  are  called  products.  When  the 


resulting  condensed  vapor  exists  in  the  same  form 
in  the  original  substance  it  is  called  an  educt.  When 
a  substance  is  easily  converted  into  a  vapor  it  is 
spoken  of  as  being  volatile.  Some  substances  can- 
not be  volatilized,  such  a  substance  is  wood.  This 
would  be  called  non-volatile.  Heat  usually  causes 
a  substance  to  change  to  vapor  and  some  substances 
become  vapors  at  lower  temperatures  than  others. 
Thus  in  a  mixture  containing  two  or  more  sub- 
stances of  widely  different  boiling  points  one  would 
expect  that  the  one  with  the  lowest  boiling  point 


FIG  1— WATER  STILL. 
A— Heard. 
B — Arm. 

C — Tank    and    worm. 
D — Receiver. 


would  vaporize  or  distill  first.  However,  with  sub- 
stances whose  boiling  points  are  near  together  one 
may  give  off  a  heavy  vapor  which  will  retard  its 
distillation.  Owing  to  this  a  general  rule  is  given 
by  Wanklyn  that  "the  quantity  of  each  ingredient 
which  distills  will  be  found  by  multiplying  its 
tension  at  the  boiling  point  of  the  mixture  by  its 
vapor  density." 

To  carry  out  the  process  of  distillation  the  ap- 
paratus consists  primarily  of  five  principal  parts: 
the  retort  or  still;  the  still  head,  sometimes  very 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


21 


complicated  in  construction  in  fractionating  stills; 
the  condenser,  comprising  tank  containing  cooling 
liquid,  if  not  air-cooled,  and  the  worm,  pipe  or 
other  device  through  which  the  vapors  pass  to  be 
cooled;  the  receiver,  comprising  any  form  of  recep- 
tacle for  catching  the  products  of  condensation* 
and  the  connections  which  are  generally  pipes  con- 
necting the  various  parts. 

In  Fig.  1  the  various  parts  of  a  common  water 
still  are  shown.  This  could  be  used  for  distilling 
other  substances  as  well  as  water,  as  it  has  all  the 


FIG    2— RETORT    AND    WORM. 

A — Retort. 

B — Arm . 

C— Tank   and   Worm. 

i) — .ueceiver. 


necessary  parts.  All  that  is  necessary  is  to  put  the 
water  in  the  still,  place  a  fire  of  some  kind  under 
it,  and  add  the  cooling  water.  Generally  there 
should  be  an  overflow  pipe  in  the  tank  so  that  the 
water  as  it  gets  hot  can  be  forced  over  with  cold 
water  admitted  at  the  bottom  to  take  its  place. 

For  destructive  distillation  a  distilling  apparatus 
would  be  more  of  the  form  shown  in  Fig.  2.  This 
form  usually  has  no  still-head. 

Our  object  being  to  distill  wood,  it  is  necessary 
to  proceed  by  destructive  distillation.  In  the  early 
treatment  of  wood  no  apparatus  was  used  to  collect 
the  vapors,  but  they  were  allowed  to  escape  into  the 
air;  the  residue  left  after  all  the  volatile  matter  . 
formed  had  been  distilled  was  the  only  valuable 
part  saved.  The  earliest  arrangement  was  to  cover 
over  the  wood  with  earth  and  set  fire  to  it  near 
the  middle  of  the  pile  and  allow  only  a  limited  sup- 
ply of  air  to  reach  it.  In  this  way  the  heat  from 


that  part  of  the  wood  which  is  burned  distills  the 
other  part,  leaving  charcoal,  as  not  enough  air  is 
admitted  to  allow  this  to  burn. 

As  this  method  of  utilizing  the  wood  may  be  the 
best  in  some  localities,  a  view  of  a  kiln  is  herein 
presented  as  illustrated  in  Wagner's  Chemical 
Technology.  This  is  called  an  Italian  kiln,  as  this 
form  is  much  used  in  Italy.  It  consists  of  three  or 
more  poles  stuck  in  the  ground  and  separated  from 
each  other  by  wedges,  N  Fig.  3.  The  wood  is 
stacked  on  end,  as  shown,  the  upper  part  being 
filled  in  with  pieces  lying  horizontally.  The  whole 
mass  is  then  covered  with  earth  and  ignited. 

Another  form  of  kiln  is  the  Slavonian,  similar  to 
the  Italian  kiln,  but  instead  of  several  poles  at  the 
axis  there  is  usually  but  one.  Also  a  passage  way 
is  made  from  the  outer  edge  of  the  kiln  at  the  bot- 
tom to  the  middle  of  the  pile,  thus  making  it  easy 
to  light  the  pile  in  the  middle. 

A  form  used  in  Norway  called  the  Schwarten  kiln 
is  suitable  for  making  charcoal  from  slabs.  For  an 
axis  several  planks  are  tied  together  and  driven 


FIG   3— ITALIAN    CHARCOAL   KILN. 
N — Wedge. 


into  the  ground;  around  the  axis  blocks  are  built 
up  to  form  a  cone-shaped  mound.  Upon  this  mound 
the  planks  or  slabs  are  placed,  leaning  on  the  edges 
instead  of  lying  flat,  thus  enabling  the  heat  to  pen- 
etrate better  into  the  mass.  A  kindling  passage  is 
left  at  the  bottom  and  the  whole  covered  with 
earth  and  ignited. 

Considerable  experience   is  necessary   to   burn   a 
kiln  so  as  to  obtain  the  most  charcoal  and  to  ob- 


THE 


22 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


tain  it  free  from  brands  or  not  thoroughly  charred 
pieces.  The  first  thing  to  do  is  to  drive  off  the 
water  with  as  little  heat  as  possible.  Considerable 
air  must  be  let  in  at  first  in  order  to  give  the  fire 
a  good  start  and  cause  it  to  spread  rapidly.  The 
escape  of  steam  and  wood  vapors  make  considerable 
noise  as  they  escape  through  the  earth  covering  and 
cause  the  earth  to  crack  and  sometimes  explode, 
making  the  heap  fall  in.  All  exposed  places  are 
quickly  covered  over.  The  nature  of  the  vapors 
emitted  from  the  cracks  determines  the  progress 
of  the  distillation,  so  as  soon  as  the  watery  vapor 


and  on  account  of  their  mound  shape,  meilers.  In 
a  horizontal  kiln,  where  the  wood  is  simply  corded, 
we  find  attempts  made  to  support  it  by  outside 
means.  A  kiln  of  this  type  is  shown  in  Fig.  4. 
Here  the  wood  is  stacked  up  and  a  frame  made  of 
posts  surrounding  it.  The  posts  are  connected  with 
slabs,  shingles,  boards  or  even  logs,  thus  forming 
an  enclosure  for  the  wood.  A  space  is  left  between 
the  stacked  wood  and  support  and  this  space  filled 
with  earth,  the  top  also  being  covered  with  earth. 
One  end  is  usually  higher  than  the  other,  as  is 
shown  in  the  illustration.  To  ignite  the  heap  a 


PIG  4— HORIZONTAL,  CHARCOAL,  KILN. 


and  the  heavy  smoke  of  the  next  stage  changes  to  a 
lighter  color  there  is  not  much  decomposable  matter 
left.  To  remove  this  without  burning  the  charcoal 
the  air  supply  is  diminished  and  the  heat  made  as 
far  as  possible  to  travel  from  the  top  to  the  bot 
torn,  and  from  the  middle  to  the  circumference. 
When  the  smoke  becomes  pale  and  blue  no  tarry 
matter  is  left  except  near  the  edp-es  of  the  kiln,  the 
blue  smoke  seen  coming  from  the  combustion  of 
the  charcoal  itself.  To  stop  this  all  the  airholes 
are  closed  as  tightly  as  possible,  and  the  kiln  allowed 
to  cool  off.  When  sufficiently  cooled  the  earth  is 
taken  off  and  any  glowing  charcoal  quenched  with 
water.  A  kiln  requires  continuous  attention  night 
and  day  until  finished.  The  time  varies  with  the  * 
size  of  the  kilns,  some  taking  as  much  as  two  weeks. 
On  account  of  the  wood  in  the  bottom  layers  being 
stood  on  end  these  kilns  are  called  standing  kilns 


door  is  left  in  the  smaller  end,  as  shown  at  C.  The 
fire  once  started  requires  only  the  attention  needed 
to  stop  cracks  and  to  fire  evenly.  As  part  of  the 
wood  becomes  charred  it  is  taken  out  through  the 
small  end.  This  form  of  kiln  is  much  used  in  Cen- 
tral Europe. 

In  this  country  charcoal  making  in  kilns  is  not 
a  very  remunerative  occupation  as  now  carried  on. 
In  the  South  it  is  carried  on  mostly  by  negroes  who 
succeed  in  making  enough  to  keep  them  from  starv- 
ing. A  kiln,  though,  such  as  the  Italian  form,  is 
so  easily  constructed  and  can  be  built  so  near  the 
raw  material  that  this  form  has  continued  to  be 
popular  through  the  ages.  There  is  no  outlay  of 
capital  for  apparatus  and  the  covering  material  is 
always  at  hand.  The  drawbacks  are  that  a  large 
amount  of  wood  is  burned,  the  dirt  gets  into  the 
charcoal,  a  great  many  brands  are  left  and  the 


THE    UTILIZATION    OF    WOOD     WASTE    BY    DISTILLATION. 


23 


charcoal  being  quenched  with  water  easily  breaks 
up. 

A  further  form  of  kiln  is  used  in  Russia  and  the 
Carolinas  for  making  pine  tar.  In  this  kiln  the  fat 
or  rich  wood  is  split  into  small  pieces  and  stacked 
in  layers.  As  the  mass  heats  the  tar  runs  to  the 
bottom  and  is  led  by  a  trough  into  a  barrel  or  pit 
in  the  ground.  This  is  still  a  definite  industry  in 
the  South  and  the  tar  thus  produced  has  a  ready 
sale.  It  is  a  great  deal  cheaper  than  it  should  be  be- 
cause of  its  being  produced  largely  by  turpentine 
hands  during  the  idle  season. 

Fig.  5  shows  two  views  of  such  a  kiln.  A  mound 
of  earth  is  made  and  the  bottom  made  V  shaped, 
forming  a  sort  of  trough  which  inclines  toward  the 
outlet  pipe.  The  bottom  is  covered  with  clay  and 
sometimes  shingles,  so  the  tar  may  be  as  free  as 
possible  from  dirt.  The  fire  progresses  from  the 
outside  to  the  middle,  being  lighted  at  the  bottom 


struction  in  the  earthen  kilns,  the  supported  kilns 
are  to  be  found  in  many  localities.  Instead  of  mak- 
ing a  supported  wall  of  boards  and  earth,  as  in  Fig. 
4,  brick  is  used  without  the  addition  of  earth  as  a 
covering.  One  of  the  earliest  forms  was  hemis- 
perical,  like  a  brick  kiln  with  the  brick  left  out  here 
and  there  near  the  top  for  air  holes.  The  wood  was 
put  in  at  the  top  and  through  a  door  at  the  bottom 
where  the  pile  was  ignited.  The  charge  was  fired 
in  the  usual  way  and  when  finished  the  charcoal 
was  allowed  to  cool  and  then  was  taken  out  through 
the  door  at  the  bottom. 

A  form  of  kiln  now  in  use  is  the  bee  hive  or  cone- 
shaped  kiln,  Fig.  6.  These  kilns  are  made  of  brick, 
usually  24  feet  in  diameter  and  24  feet  high,  hold- 
ing about  forty  cords  of  wood.  The  bricks  are  laid 
in  a  circle  two  courses  thick,  one  of  fire  brick  and 
one  of  red  brick  until  about  half  way  up  when  the 
remainder  is  finished  with  one  course  of  red  brick. 


FIG   5— TAR    KILN. 


and  the  vapors  escaping  at  the  top.  Most  of  the 
charcoal  is  consumed,  as  the  chief  object  is  to  obtain 
the  tar.  The  tar  collects  at  the  bottom  of  the  kiln 
and  is  taken  out  at  regular  intervals,  generally 
every  morning.  It  is  generally  several  days  before 
it  commences  to  run  and  it  is  usually  hot.  To  keep 
it  from  igniting  it  is  led  at  least  three  feet  from  any 
flame.  This  tar  was  usually  put  in  barrels  contain- 
ing about  320  pounds  and  made  on  the  spot;  now 
the  tendency  is  to  sell  in  old  oil  barrels  containing 
fifty  gallons  and  quotations  are  now  largely  made 
on  that  basis.  Notwithstanding  the  ease  of  con- 


To  strengthen  the  walls  bands  of  iron  are  placed 
at  intervals  and  tightened  with  a  bolt,  as  shown  at 
B.  It  is  claimed  by  some  that  brick  kilns  are  not 
as  good  as  the  earth-covered  mound  or  meiler,  but 
experiments  and  practice  show  a  yield  of  45  bushels 
of  charcoal  against  35  bushels  from  the  meiler,  and 
at  some  iron  furnaces  the  charcoal  is  said  to  work 
better.  The  difference  in  the  yield  is  sufficient 
to  pay  for  the  extra  expense  for  the  brick. 

In  this  kiln  the  two  doors  shown  are  of  iron  and 
on  hinges.  The  upper  one  serves  for  putting  in 
wood  and  the  lower  one  for  putting  in  wood  and 


24 


THE    UTILIZATION    01'    WOOD    WASTE    BY    DISTILLATION. 


A 


FIG  6— BEE  HIVE  OVEN. 
A— Draft  holes. 
B — Tightening   bolts. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


taking  out  the  charcoal.  At  the  bottom,  spaces  are 
left  for  the  admission  of  air;  these  can  be  stopped 
up  with  loose  brick  when  necessary. 

Another  form  of  brick  kiln  is  shown  in  Pig.  7. 
This  is  square  in  front  with  an  arched  top.  It  is 
usually  built  16  feet  wide  by  16  feet  high  and  runs 
back  about  40  feet,  outside  measure.  This  will  hold 
about  80  cords.  This  size  is  usually  built  a  brick 
and  a  half  thick  and  supported  with  10x10  frame 
work  timber.  The  cost  of  such  a  kiln  in  any  locality 
can  be  readily  calculated.  The  working  of  the  kiln 
is  similar  to  the  bee  hive,  the  doors  being  for 
charging  and  discharging  and  the  holes  at  the  bot- 
tom being  for  the  admission  of  air. 

In  .all  these  kilns  no  attempt  was  made  until  re- 
cently to  save  the  vapors.  In  Michigan  connecting 
pipes  have  been  added  for  some  time,  but  the  prac- 
tice did  not  become  universal.  It  is  not  difficult  to 
save  the  vapors  from  the  brick  kilns,  all  that  is 
necessary  being  to  lead  the  vapors  through  a  con- 
denser by  means  of  a  suitable  pipe.  Different  meth- 
ods of  distilling  with  the  object  of  saving  the  vapors 
will  be  taken  up  in  the  next  chapter. 


.  I  .  il I  .   I  .  I  .   I   ,   I  ,  I 


rn  '  i '  i ' i    i     I  .  i    i 


FIG   7— RECTANGULAR   BRICK  KILN. 


CHAPTER  IV. 

APPARATUS  NECESSARY  FOR  DESTRUCTIVE  DISTILLATION. 


As  has  been  previously  stated,  the  necessary  ap- 
paratus for  destructive  distillation  consists  of  a 
retort,  arm  or  connecting  pipe,  condenser  and  re- 
ceiver. The  earliest  forms  of  retorts  were  prob- 
ably the  brick  kiln.  This  form  is  to  be  distin- 
guished from  the  iron  retort  in  that  air  has  limited 
access  to  it,  whereas  an  iron  retort  is  usually  a 
closed  vessel,  being  as  air-tight  as  possible. 

In  Sweden  the  brick  kiln  was  modified  from 
those  previously  described,  when  the  advisability 
of  saving  the  vapors  became  of  sufficient  impor- 
tance. The  connecting  pipe  made  a  definite  outlet 
for  the  products  of  combustion  and  a  means  was 
soon  devised  to  regulate  the  supply  of  air.  The 
Swedish  oven,  so-called,  which  was  thus  evolved, 
took  the  form  as  shown  in  Fig.  8.  This  is  a  hemis- 
pherical shaped  kiln  or  oven  with  an  opening  at 
the  top  A  with  cover  B  by  means  of  which  the  wood 
can  be  dropped  in.  At  C  is  a  door  serving  the 
double  purpose  of  allowing  the  wood  to  pass  in 
and  as  an  opening  for  drawing  out  the  char- 
coal. At  D  is  another  door  controlling  the  air 
supply  which  passes  along  the  passageway  E  to 
the  grate  F  upon  which  the  wood  is  placed.  The 
heat'  for  charring  is  supplied  by  the  combustion 
of  a  part  of  the  wood  in  the  oven,  the  vapors  and 
gases  from  the  combustion  passing  through  the 
pipe  G  to  the  condenser.  The  size  of  the  grate 
can  be  varied  to  suit  circumstances.  As  shown, 
this  oven  takes  a  great  many  bricks,  but  it  can 
be  made  of  less  thickness;  the  extended  doorway 
at  C  can  be  omitted  and  the  door  placed  directly 
in  the  wall. 

In  this  country  in  the  Pierce  process  ovens  the 
shape  of  a  brick  kiln  are  employed.  The  uncon- 
densable  gases  formed  are  led  under  the  kiln  and 
burned  with  just  enough  air  for  combustion  and 
the  heated  gas  is  passed  directly  through .  the 
spaces  between  the  wood  in  the  kiln.  This  proc- 
ess will  be  described  later. 


An  attempt  was  made  by  Hahnemann  to  heat 
the  wood  from  the  top  of  a  brick  kiln  with  a  cylin- 
drical shaft  in  the  middle  with  openings  at  the 
bottom  so  that  the  gases  of  combustion  could  pass 
down  through  the  wood,  and  by  following  the  shaft 
escape  at  the  top  into  the  air.  A  pipe  at  the  bottom 
v/as  supposed  to  carry  off  the  vapors.  It  can  be 
readily  seen  that  the  light  vapors  from  the  distilla- 
tion would  also  escape  at  the  top. 

A  modification  of  the  bee-hive  form  was  also 
constructed.  This  had  an  inner  cone  for  the  wood 
and  the  space  between  the  two  walls  was  used  as 
a  furnace  to  heat  the  inner  wall.  The  products  of 
the  distillation  passed  out  at  the  bottom.  The 
idea  was  a  good  one,  but  the  furnace  is  not  of  the 
best  form  to  get  satisfactory  results  from  the  fuel. 

To  heat  the  wood  in  a  retort,  and  at  the  same 
time  not  have  the  flame  from  the  fire  to  touch  it, 
Reichenbach  devised  an  oven  consisting  of  a  rect- 
angular brick  chamber  made  as  air-tight  as  pos- 
sible, and  mounted  with  suitable  doors  for  the  ad- 
mission of  the  wood.  The  furnace  gases  were  then 
passed  through  the  chamber  by  means  of  large 
closed  pipes.  These  pipes  becoming  red  hot,  the 
heat  was  communicated  to  the  wood  and  the  con- 
tents of  the  oven  distilled.  The  vapors  and  tar 
formed  were  taken  off  at  the  bottom. 

It  is  evident  that  ovens  have  many  disadvan- 
tages as  a  means  of  carbonizing  wood  for  the  re- 
covery of  the  liquid  products  of  distillation.  As 
the  desirability  of  excluding  the  furnace  gases  be- 
came apparent,  apparatus  was  devised  that  would 
more  readily  transmit  heat.  Cast-iron  was  resort- 
ed to,  then  clay,  and  then  wrought  iron  and  steel. 
At  the  present  time  most  retorts  are  made  of 
boiler  plate,  although  some  use  cast-iron  and  a  few 
clay.  A  clay  retort  does  not  readily  burn  through, 
but  it  is  difficult  to  keep  them  tight,  as  they  are 
so  apt  to  crack,  thus  causing  them  to  leak  when 
under  pressure.  Cast-iron  retorts  are  made  thick 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


27 


in  order  to  have  strength  and  have  an  advan- 
tage over  wrought-iron  in  that  they  do  not  readily 
burn  through.  They  are  also  liable  to  crack,  and 
when  the  crack  is  large  a  disastrous  explosion  will 
ensue;  also  they  cannot  be  repaired  easily. 

A  boiler  plate  retort  offers  many  advantages  in 
that  being  thinner,  the  heat  is  more  readily  trans- 
mitted, and  although  they  may  sometimes  crack 
from  unequal  expansion  and  contraction,  and  are 
sure  to  burn  through  sooner  or  later,  still  they 
can  be  easily  repaired  by  patching  either  with  a 
bolt  patch  with  gasket  or  preferably  by  riveting. 

Clay  retorts  are  generally  of  one  form,  the 
Q  shape  of  the  coal  gas  retort,  and  are  used 
in  a  similar  manner.  Cast-iron  retorts  are  usually 
simple  in  shape  and  are  like  some  forms  of  ver- 
tical and  horizontal  steel  retorts.  Wrought  iron  or 


steel  retorts  assume  various  shapes;  some  are 
rectangular  boxes,  some  are  boiler  shaped  cylin- 
ders and  some  are  of  irregular  shapes. 

Ovens  or  boxes  are  not  used  in  the  pine  wood 
distillation,  but  could  be.  These  ovens  are  set 
in  pairs  in  brickwork  and  are  provided  with  large 
doors  at  one  end  and  three  or  more  delivery  pipes 
at  the  side  of  each  oven.  They  are  usually  27 
feet  long,  6  feet  wide  and  7  feet  high  inside,  and 
rails  are  laid  upon  the  floor  of  the  oven  by  which 
steel  cars  loaded  with  cord  wood  can  be  run  in. 
These  cars  hold  2%  cords  of  wood,  and  an  oven 
of  this  size  will  hold  two  cars.  Some  ovens  are  . 
48  to  50  feet  long  and  capable  of  receiving  four 
cars  at  one  charge.  These  ovens  are  much  used 
in  localities  where  there  is  natural  gas  for  fuel. 

The  pine  wood  distiller  has  had  more  experience 


FIG    8— SWEDISH    OVBN. 
A — Air  opening. 
H — Cover. 
O— Door. 

D — Air   supply    door. 
E — Passage  way. 
F — Grate . 
(J — Pipe  to  condenser. 


28 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


with  cylindrical  iron  retorts.  These  are  made  of 
all  shapes  and  sizes,  varying  more  to  obtain  patent 
than  for  practical  utility. 

The  size  of  retort  for  turpentine  distillation 
seems  to  be  an  unsettled  controversy.  Some  claim 
small  retorts  are  more  efficient  and  some  claim 
that  large  ones  are  better.  In  reality  much  de- 
pends upon  the  method  of  working  and  the  prod- 
ucts sought.  One  thing  is  certain,  and  that  is 
that  a  large  retort  cannot  be  heated  in  the  middle 
as  easily  as  a  small  one  when  the  heat  is  applied 
by  external  firing.  Wood  is  a  non-conductor  of 
heat,  and  if  the  retort  is  well  filled,  as  it  should 
be  to  save  space,  the  wood  near  the  shell  of  the 
retort  is  bound  to  be  burned  before  that  in  the 
middle  has  been  thoroughly  charred.  This  was 
one  reason  why  Reichenbach  put  pipes  in  his  kiln 
as  mentioned  before,  so  that  the  heat  could  be 
more  evenly  distributed.  To  offset  this  apparent 
disadvantage,  users  of  large  retorts  try  to  make 
use  of  the  radiating  power  of  heated  brick.  This 
is  exemplified  by  the  working  of  a  baker's  oven, 
in  making  bread,  the  radiated  heat  from  the  vault- 
ed arch  concentrating  at  a  common  center  makes 
the  heat  in  the  middle  greater  than  it  otherwise 
would  be,  thus  the  inner  part  of  the  loaf  is  cooked 
without  burning  the  outside. 

With  ordinary  firing  of  a  retort  only  portions  of 
a  shell  are  heated  to  the  same  degree,  but  with 
radiated  heat  the  temperature  is  kept  more  even. 
Although  a  large  retort  sems  to  be  a  disadvantage 
when  fired  by  a  direct  heat,  such  cannot  be  the 
case  in  the  steam  process  for  extracting  turpentine 
where  steam  alone  is  used.  Here  the  steam  can 
come  in  direct  contact  with  all  of  the  wood  alike; 
in  fact,  it  can  be  placed  in  the  middle  if  need  be. 
In  this  process,  then,  the  only  limit  to  the  size  of 
the  retort  need  be  the  mechanical  drawback  inci- 
dent to  the  rapidly  filling  and  discharging  when  in- 
termittent processes  are  used. 

In  early  practice  with  retorts  they  were  made  of 
such  a  size  as  to  allow  the  contents  to  be  thor- 
oughly charred  in  twelve  hours  with  the  necessary 
conditions  for  yielding  the  nr?3t  products.  Thus 
we  find  retorts  5%  to  Gy2  fee:  long  with  a  diam- 


eter of  2}4  to  3^  feet  for  ho.-izontal  retorts  and 
for  vertical  ones  a  diameter  of  4  to  5  feet  and  a 
height  of  7i/2  feet. 

Gradually  the  size  has  been  increased  until  now 
we  have  them  of  such  a  size  that  they  can  b& 
charred  and  emptied  in  24  hours. 

Retorts  used  in  the  hardwood  industry,  and  now 
used  with  some  success  with  pine,  are  made  about 
9  feet  long  and  about  50  inches  in  diameter  and 
are  provided  with  tightly  fitting  doors  and  an  out- 
let pipe  of  about  15  inches  for  the  vapors  They 
are  sometimes  set  in  pairs,  sometimes  single  and 
sometimes  not  protected  from  the  direct  flame, 
but  should  be,  as  they  will  not  burn  out  so  readily 
nor  buckle  so  easily.  These  retorts  hold  less  than 
a  cord,  so  in  the  pine  wood  distillation  it  is  better 
to  increase  the  diameter  about  6  inches  so  that 
they  will  hold  a  full  cord.  Cars  are  seldom  used 
on  retorts  of  this  size,  as  they  cut  down  the  space. 
The  thickness  of  the  retort  varies  with  the  size, 
a  one  cord  retort  being  %  to  y2  inches  thick.  Ver- 
tical retorts  ate  built  about  this  same  size. 

Other  sizes  are  to  be  found,  though,  in  the  pine 
wood  distilleries,  varying  from  3  to  9  feet  in  di- 
ameter and  5  to  30  feet  long. 

In  designing  a  retort  there  are  certain  things 
to  be  taken  into  consideration  when  external  heat 
is  applied.  There  is  no  perfect  retort  for  wood 
distillation,  nor  can  there  be,  for  such  a  retort 
would  require  that  every  part  of  the  wood  should 
be  heated  to  the  same  degree  of  heat  at  the  same 
!  time  and  for  the  same  length  of  time.  If  such 
a  one  were  constructed  it  would  not  be  possible 
to  charge  it.  One  would  think  that  a  large  cylin- 
drical retort  of  very  small  diameter  would  be  the 
best.  Such  would  be  the  best  as  far  as  heating 
the  middle  is  concerned,  but  we  find,  unfortunate- 
ly, that  the  vapors  evolved  are  themselves  decom- 
posed when  kept  in  contact  with  the  hot  sides  of 
a  retort,  as  they  would  be  in  passing  from  one 
end  to  the  other.  This  might  be  obviated  by  hav- 
ing several  openings  for  vapors  to  escape,  but  this 
would  necessarily  increase  the  cost  of  construc- 
tion. To  get  the  .capacity  and  at  the  same  time 
to  avoid  having  the  length  too  long  and  the  di- 


THE    UTILIZATION    OF    WOOD     WASTE    BY    DISTILLATION. 


29 


ameter  too  great,  we  find  that  the  compromise 
is  effected  by  having  the  retorts  of  such  a  length 
that  but  little  decomposition  takes  place  and  of 
such  diameter  as  to  enable  the  charge  to  be  fin- 
ished in  a  given  time. 

A  horizontal  retort  is  shown  in  Fig.  9.  This 
shows  a  larger  size  fitted  with  rails  for  a  car  of 
wood.  Retorts  of  this  class  when  the  wood  is  to 
be  destructively  distilled,  should  be  made  of  as 
good  steel  as  possible,  with  a  high  tensile  strength 
and  with  as  few  sections  as  possible.  The  size  should 
be  arranged  so  as  to  allow  of'  its  being  made  of 


one  end  of  the  retort  which  fit  with  corresponding 
rings  in  the  doors.  By  the  use  of  bolts  or  wedges 
the  doors  can  thus  be  tightly  fastened.  If  the 
doors  are  small  they  are  hung  on  hinges,  but  if 
large  it  is  necessary  to  have  a  wheel  on  the  bot- 
tom to  support  the  weight  when  the  door  is 
opened.  Sometimes  the  doors  are  counterbalanced 
by  weights  similar  to  a  dry  kiln  door,  and  some- 
times hoisted  by  suitable  hoisting  machinery,  such 
as  engine,  winch,  crane  or  crab. 

To  support  a  retort  in  a  furnace  it  is  preferable 
to  keep  all  the  weight  away  from  the  brickwork. 


D 


OOOOOOOOOOOOOOOOOOOOOOOOOOOOO 


FIG.    9. 

A — Exit  pipe  to  condenser. 

B — Car    stop. 

C — Ca^t  iron  ring. 

D — Supporting    rod. 

E — Lug. 

F — Steam    pipe. 

G — Track. 


commercial  sizes  of  steel.  The  various  sections 
cannot  be  rivetted  too  carefully,  as  a  defective 
rivet  is  very  troublesome,  particularly  if  in  a  po- 
sition that  is  difficult  to  get  at.  If  possible,  the 
various  pipes  should  be  so  connected  that  the  re- 
tort might  be  turned  when  it  begins  to  burn.  Out- 
let pipes  should  be  as  large  as  possible,  so  as  to 
allow  of  the  rapid  escape  of  the  vapors.  Arrange- 
ments should  be  made  to  allow  the  placing  of  a 
pyrometer  and  any  necessary  gauges.  To  make  the 
heads  tight  cast-iron  rings  are  usually  placed  in 


This  can  be  done  conveniently  either  by  hanging 
by  means  of  rods  from  I  beams  or  by  using  lugs 
similar  to  those  found  on  boilers,  and  placing  iron 
pipes  or  posts  under  the  lugs,  in  all  cases  allow- 
ing for  the  expansion  of  the  retort.  Whatever 
means  of  support  used,  any  part  of  the  support  ex- 
posed to  the  direct  action  of  the  fire  should-  be 
made  of  cast-iron  or  some  material  not  easily 
burned. 

A  retort  furnace  should  be  made  of  brick  and 
well  lined  with  fire  brick.    A  furnace  suffers  great- 


30 


THE    UTILIZATION    OF    WOOD    WASTE     I*Y     DISTILLATION. 


ly  from  the  continual  heating  and  cooling  incident 
to  distilling.  Only  the  best  work  of  the  masons 
is  suitable  for  the  purpose.  The  joints  should  be 
made  thin  and  the  fire  brick  should  be  laid  with 
a  coating  only  of  the  best  fireclay,  that  kind  from 
which  brick  was  made  being  preferable. 

To  support  the  furnace  walls  a  boiler  front  is 
very  satisfactory  and  adds  greatly  to  the  appear- 
ance. The  brickwork  in  horizontal  retort  furnaces 
that  is  just  above  the  retort  has  a  tendency  to 
crack,  so  the  boiler  front  should  extend  around 
the  top  of  the  retort.  The  walls  through  and 
through  should  be  suitably  tied  with  long  rods,  an- 
chor rods  not  being  as  good.  A  buckstay 
placed  horizontally  above  the  rear  end  of  the  re- 
tort and  connected  with  the  boiler  front  with  a 
long  bolt  will  help  the  back  wall.  Furnaces  made 
with  these  precautions  are  found  to  give  but  little 
trouble.  Arrangements  can  be  made,  and  one 
form  is  the  subject  of  a  patent  by  means  of  which 
small  rollers  can  be  placed  in  the  cooler  parts  of 
the  brickwork. 

The  retort  can  be  lowered  on  these  rollers  and 
turned,  thus  exposing  a  new  surface  to  the  hottest 
part  of  the  fire  when  one  part  is  burned. 

A  vertical  retort  and  setting  is  shown  in  Fig.  10. 
The  same  rule  applies  with  these  as  with  horizontal 
retorts.  As  the  vapors  rise  they  are  apt  to  be  de- 
composed at  the  top,  as  the  heat  of  the  furnace 
naturally  rises.  By  keeping  the  bottom  cool  they 
fierve  as  a  ready  means  of  extracting  tar,  although 
a  great  deal  of  retort  capacity  is  lost,  as  the  wood 
ought  not  to  be  placed  where  the  heat  cannot  thor- 
oughly char  it.  These  vertical  retorts  are  much 
used  in  France  and  have  the  advantage  that  they 
can  be  lifted  out  of  the  furnace  by  means  of  a 
crane  and  a  new  retort  filled  with  wood  placed  in 
while  the  other  is  cooling.  Modifications  of  this 
idea  are  found  in  the  South  and  West.  One  plant 
at  Georgetown,  S.  C.,  uses  a  brick  retort  and  runs 
in  a  basket.  On  the  Pacific  coast  an  iron  retort 
is  used  instead  of  the  brick.  It  is  fitted  with  an 
open  work  basket  and  this  is  lowered  into  the  re- 
tort, filled  with  wood,  the  retort  cover  bolted  on 
and  the  wood  distilled  and  the  charcoal  immedi- 


FIG.  10— VERTICAL  RETORT. 
A — Retort. 

B — Combustion  chamber. 
C— Ash    pit. 


aiely  lifted  into  an  iron  cooler.  This  saves  the 
wear  and  tear  on  the  retort  and  furnace.  The  dis- 
tilled products  go  out  at  the  bottom.  In  some  ver- 
tical retorts  they  are  made  slanting  to  let  the 
charcoal  slide  out  at  the  bottom. 

There  are  several  kinds  of  special  retorts,  but 
most  of  them  deal  with  sawdust  or  hogged  wood. 
There  are  but  three  that  claim  to  be  continuous  in 
operation,  the  remainder  being  intermittent.  One 


THE    UTILIZATION    OP    WOOD    WASTE    BY    DISTILLATION. 


31 


form,  the  Bowles  patent,  is  said  to  be  in  successful 
operation  with  hardwood  sawdust.  The  object  of 
a?l  seems  to  be  to  stir  up  the  wood  so  that  the 
steam  can  play  more  readily  upon  the  surfaces  of 
the  pieces  and  also  to  prevent  the  formation  of 
channels.  These  forms  will  be  described  under 
PROCESSES. 

Charcoal  Coolers. — These  consist  of  sheet  iron 
Voxes  made  for  use  with  those  retorts  where  the 
charcoal  is  taken  out  hot.  They  have  a  form  cor- 
responding to  the  use  to  which  they  are  to  be  put. 
Where  cars  are  used  they  are  pulled  out  hot  and 
run  into  a  box  of  a  suitable  shape.  Where  baskets 
are  used  they  are  drawn  into  cylinders  of  similar 
size  and  shaped  to  the  retort.  In  another  form 
sheet  iron  cars  are  run  up  to  the  door  of  the  re- 
tort, the  door  opened  and  the  charcoal  quickly 
raked  out  into  the  car,  a  cover  put  on  and  the 
edges  luted  with  clay  and  the  whole  wheeled  away 
to  cool. 

Connections. — The  connecting  pipes  between  re- 
tort and  condenser  should  be  as  short  as  possible 
vhere  direct  connection  is  made  between  each  re- 
tort and  a  condenser.  In  some  plants  several  re- 
torts are  connected  'With  one  condenser.  In  these 


cases  a  long  main  pipe  is  necessary  and  some  way 
must  be  devised  to  keep  the  vapors  from  one  re- 
tort getting  to  the  other.  This  can  be  done  by 
means  of  valves  or  by  a  hydraulic  seal,  such  as  is 
used  in  the  hydraulic  main  of  gas  works.  The  lat- 
ter method  is  much  to  be  preferred,  as  valves  stick 
and  if  large  and  made  out  of  iron  are  gradually 
eaten  by  the  acetic  acid  vapors  and  are  not  tight. 
On  account  of  the  destructive  action  of  these  va- 
pors upon  iron  it  is  advisable  to  use  copper  which 
is  little  attacked.  C^st  iron  is  better  than  wrought 
iron,  which  should  not  be  used  at  all.  These  pipes 
should  all  be  large  and  so  arranged  as  to  be  easily 
cleaned;  it  is  better  to  get  cooling  water  on  them 
in  some  way,  as  this  will  prevent  the  formation  of 
a  deposit  of  tarry  matters  that  would  otherwise 
adhere  strongly  to  the  pipe.  This  cooling  is  very 
important  when  working  with  wood  rich  in  resin 
and  tar.  The  size  of  these  pipes  can  be  determined 
by  calculating  the  amount  of  vapors  evolved  (see 
yields)  from  the  wood  in  a  given  time,  the  vapors 
occupying  at  least  1,000  times  more  space  than  the 
liquid  products.  To  be  safe  make  it  1,700  times, 
which,  with  the  cooling  effect  of  the  air  or  water 
on  the  connecting  pipes,  will  leave  room  for  the 


FIG.  11. 

A — Pipes  from  retorts. 
B — Hydraulic    seal. 
C — Hydraulic    main. 
j> — Overflow  pipe  to  receiver. 
E — Main   pipe   to  condenser. 


32 


THE    UTILIZATION    OF    WOOD    WASTE     BY    DISTILLATION. 


rapid  exit  of  the  gases.  There  should  not  be  over 
one  pound  pressure.  The  pressure  being  small, 
the  thickness  is  only  great  enough  to  make  the 
pipe  of  sufficient  rigidity  to  stand  outside  strains. 
Of  course,  in  steam  pressure  turpentine  retorts  the 
thickness  must  be  large  enough  to  stand  the  strain 
from  the  inside.  See  Fig.  11  for  illustration  hy- 
draulic main.  In  addition  to  the  connections  be- 
tween retorts  and  condensers  it  is  necessary  to 
pipe  the  gas  either  to  a  holder  or  to  the  furnace. 
The  gas  is  separated  from  the  condensed  prod- 
ucts in  the  condenser  by  means  of  several  devices, 
the  most  simple  of  which  is  shown  in  Fig.  12  A. 
This  consists  of  nothing  but  a  brass  T,  the  liquid 


A — Gas  to  air. 

falling  and  the  gas  rising  being  kept  from  follow- 
itg  the  liquid  by  means  of  the  goose  neck,  as 
shown.  If  the  pressure  became  too  high  the  liquor 
in  the  bend  might  blow  out  and  the  gas  escape. 
Gas  valves  are  sometimes  carelessly  left  closed, 
and  this  blowing  out  would  at  once  give  warning. 
Ihe  pipe  carrying  the  gas  should  be  made  of  cop- 
per, but  as  most  of  the  acid  is  taken  out  of  the 
gas  other  materials  are  often  used,  as  copper  is 
very  expensive.  A  wooden  pipe  would  be  a  very 
suitable  pipe.  By  giving  the  pipe  a  backward  slope 
liquid  products  that  might  be  mechanically  carried 
along  with  the  gas  would  fall  back.  By  placing  a 
box  with  lime  in  connection  with  the  pipe  the  acid 


would  be  caught  and  the  pipe  would  be  free.  This 
box  would  have  to  be  cleaned  and  fresh  lime  added 
from  time  to  time,  the  acetic  acid  being  saved 
where  acetate  was  made  regularly.  Another  form 
of  separator  is  shown  at  B,  Fig.  12,  and  another  at 
C,  Fig.  12.  The  one  at  B  is  used  at  several  places  in 
the  South.  In  this  form  the  gas  escapes  from  the 


A — Gas    to    air. 

B — Gas    to    furnace. 

C — From    condenser. 


top  of  the  cone-shaped  head  and  the  liquor  is  drawn 
off  by  means  of  the  cocks,  through  the  funnels 
shown,  connected  with  pipes  leading  to  tanks 
raade  to  receive  the  several  products  of  distilla- 
t:on,  such  as  turpentine,  tar-oil  and  tar.  In  the 
one  at  C,  used  at  Lake  Charles,  La.,  the  end  of 
the  condenser  is  led  under  the  liquid,  thus  form- 
ing a  hydraulic  seal  to  prevent  the  gases  from  re- 


'THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


33 


turning  to  the  retort,  if  for  any  reason  the  gas 
should  explode  or  the  retort  cool  off  suddenly. 
This  causes  only  a  slight  back  pressure,  as  the 
end  of  the  condenser  only  dips  under  the  liquid 
about  three-fourths  of  an  inch.  This  contrivance 
aiso  causes  a  steady  flow  of  condensed  products 
from  the  goose-neck  outlet. 

Sometimes  other  contrivances  are  placed  in  the 


FIG.  12-C. 
A — Gas    outlet. 
B — From  condenser. 


connecting  pipes,  such  as  tar  separators,  vapor  ab- 
sorbers and  milk  of  lime  receptacles,  but  the  best 
practice  seems  to  be  to  get  the  product  out  of  the 
wood  as  soon  as  possible  and  do  the  refining  after- 
wards in  more  suitably  constructed  refining  ap- 
paratus. When  the  condensed  products  are  not 
caught  directly  in  the  receivers,  a  pipe  or  trough 
is  used  to  convey  them  to  the  receivers.  As  a  gen- 


eral rule,  whenever  the  vapor  contains  acid,  all 
pipes  and  vessels  should  be  made  of  copper  or 
wood.  We  find  wooden  troughs  very  extensively 
used  for  conveying  the  liquors. 

Condensers. — One  of  the  most  important  parts 
of  a  wood  distilling  plant  is  the  condenser.  There 
are  three  general  forms  used,  namely,  the  worm, 
tubular  and  box  condensers.  In  addition  to  these 
fiere  are  modifications  of  the  three.  The  efficiency 
of  a  condenser  depends  upon  the  amount  of  cooling 
element  and  the  length  of  time  each  particle  of  the 
vspors  is  allowed  in  contact  with  the  cooling  sur- 
face. They  should  be  made  of  copper  where  there 
is  acid. 

Small  tubes  offer  more  surface  in  proportion  to 
their  cubic  contents  than  large  ones,  consequently 
we  find  that  tubular  condensers  are  made  with  nu- 
merous small  tubes  rather  than  with  a  few  large 
ones.  However,  they  must  not  be  too  small  in  the 
larger  sizes  of  condensers.  A  worm  condenser 
raust  be  made  large,  in  order  to  take  the  large  vol- 
ume of  Vapor;  as  the  vapor  condenses  the  pipe  can 
be  made  smaller  toward  the  end.  These  large 
pipes  increase  the  cooling  surface  in  this  form  of 
9.  condenser,  for  they  must  be  made  just  as  long 
as  a  small  pipe  having  enough  cooling  surface,  be- 
cause the  gases  and  vapors  would  pass  through  a 
short  condenser  before  the  middle  current  in  a 
large  pipe  would  have  time  to  strike  the  cooling 
walls  and  be  condensed.  It  seems  to  be  a  rule  with 
gases  and  vapors  that  they  cannot  be  heated  or 
cooled  very  rapidly  unless  they  come  in  contact 
with  some  solid  substance,  in  the  above  case  the 
walls  of  the  pipe.  For  this  reason  the  box  form  of 
a  condenser  is  not  very  efficient,  owing  to  the  large 
volume  of  vapor  present  in  the  chamber  at  one 
time  in  comparison  to  the  cooling  surface.  The 
most  efficient  condenser  costs  the  most,  hence  we 
find  that  the  other  forms  are  used  in  preference 
on  account  of  original  cost  only. 

The  vapors  from  the  distillation  of  wood  are  of 
such  a  nature  that  it  is  absolutely  necessary  to 
cool  them  thoroughly,  otherwise  some  of  the  va- 
I'ors  will  get  into  the  gas  pipe  and  not  only  tend 
to  destroy  it,  but  will  themselves  be  lost.  Further- 


34 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


nwre,  it  is  advisable  to  cool  them  quickly  so  as  to 
relieve  any  pressure  that  might  form  in  the  retort. 
The  more  pressure  in  the  retort  the  more  tar.  etc., 
•will  be  decomposed,  forming  permanent  gases.  In 
reality,  some  form  of  exhauster  ought  to  be  used 
in  destructive  distillation  plants,  so  as  to  remove 
the  products  of  distillation  rapidly  and  thus  pre- 
vent the  decomposition  in  the  retorts.  Many  plants 
are  now  introducing  such  apparatus.  Any  form 
of  rotary  exhauster,  such  as  are  used  in  coal  gas 
works,  would  be  especially  adapted  for  this  purpose. 
A  condenser  for  wood  distilling  comprises  in  ad- 
dition to  the  worm,  etc.,  a  tank  of  some  kind  to 
contain  the  condensing  water.  These  tanks  can  be 
made  of  wood  or  of  tank  steel  and  should  be  pro- 
vided with  an  inlet  pipe  at  the  bottom  for  cold 
water  under  pressure  and  with  an  outlet  pipe  at 
the  top  to  remove  the  hot  water  forced  over  by  the 
•  cold  water  coming  from  below.  In  this  way  the 
nearly  cooled  vapors  coming  in  contact  with  the 
walls  of  the  pipe  cooled  by  this  entering  cold  wa- 
ter become  completely  cooled  and  at  the  same 
time  the  hot  water  at  the  top  being  much  cooler 
than  the  incoming  vapors,  also  has  a  cooling  effect, 
and  thus  the  water  is  used  very  effectively.  An 
iron  tank  is  better,  as  it  is  not  so  apt  to  leak. 

On  account  of  the  desirability  of  cooling  the  va- 
pors quickly  those  plants  using  a  main  line  for  all 
the  retorts  should  make  provision  for  cooling  this 
pipe  with  water.  The  surface  of  the  pipe  would 
in  this  way  act  very  effectively  in  cooling  off 
the  vapors.  Furthermore,  these  main  pipes  get 
very  hot  and  sometimes  the  heat  becomes  so  great 
as  to  carbonize  some  of  the  vapors  and  a  heavy 
deposit  is  formed  that  is  sometimes  difficult  to 
remove  and  might  at  times  block  the  pipe.  With 
water-cooled  pipes  this  would  not  happen.  The 
heavy  tar  vapors  would  condense  in  this  main 
and  flow  out  the  overflow  pipe  shown  ia  Fig.  11, 
and  thus  reach  the  receiver.  The  first  part  then 
of  the  condensing  apparatus  should  be  the  hydraul- 
ic main  when  such  is  used. 

In  some  plants  making  wood  turpentine  by  th? 
destructive  distillation  method  in  order  to  avoid 
the  bad  odor  that  is  so  difficult  to  remove  from 


the  turpentine  produced,  two  sets  of  condensers 
are  used.  In  such  cases  the  only  way  to  direct 
the  vapors  is  by  means  of  valves.  The  connecting 
pipe  must  be  cooled  and  the  water  surround  the 
valve  or  a  great  deal  of  trouble  will  be  caused  by 
the  valve  sticking  generally  from  the  tar,  etc.,  geN 
ting  on  to  the  threads  of  the  stem.  Where  the 
turpentine  is  distilled  (generally  through  a  small 
pipe)  a  valve  is  turned  off  and  a  larger  one  leading 
to  the  other  condenser  is  opened  and  the  distilla- 
tion is  continued.  Except  for  a  very  particular 
grade  of  goods  this  method  is  not  to  be  commend- 
ed as  it  entails  an  extra  expense  for  a  second  con- 
denser and  also  for  a  very  large  valve  which  if 
made  out  of  brass,  as  it  ought  to  be,  would  be 
very  expensive,  and  if  made  of  cast  iron  the  threads 
of  the  seat  would  eventually  be  eaten  out  by  the 
vapor  and  the  valve  practically  destroyed.  If  a 
Reparation  of  the  distilled  products  is  to  be  made 
it  should  be  made  at  the  end  of  the  condenser  sim- 
ilar to  the  method  pursued  in  distilling  petroleum; 
any  small  amount  of  tarry  matter  in  the  con- 
denser remaining  after  the  distillation  could  be  re- 
moved, either  by  washing  or  draining,  or  if  mixed 
with  the  first  runnings  of  the  next  turpentine  dis- 
tillate it  can  be  sufficiently  removed  by  the  refining 
process  used. 

Box  Condenser. — This  form  of  a  condenser  is  sim- 
ply a  rectangular  receptacle  made  of  copper  for 
receiving  the  vapors.  It  has  the  necessary  inlet 
p;pe  for  the  vapors  and  an  outlet  pipe  for  the  con- 
densed product.  It  is  placed  in  a  wooden  or  iron 
tank  containing  the  condensing  water.  In  the  Bil- 
finger  process  this  inner  chamber  is  lined  with 
wood.  A  reversal  of  this  system  might  be  better 
by  putting  the  cooling  water  inside  and  the  vapors 
iu  an  outer  chamber;  it  would  have  the  advantage 
of  being  cooled  some  by  the  outside  air,  and  at 
the  same  time  have  a  little  more  cooling  surface 
on  the  water  side.  It  might  be  a  little  more  diffi- 
cult to  construct,  but  would  need  less  material  to 
get  the  same  effect  if  iron  were  used  in  its  con- 
struction. With  copper  the  cost  would  be  much 
increased  as  there  would  be  four  extra  walls. 

Worm. — The  next  simplest  condenser  is  the  worm. 


THE    UTILIZATION    OF    WOOD    WASTE     BY    DISTILLATION. 


35 


As  before  stated,  one  end  must  be  very  large  in 
order  to  receive  the  large  volume  of  vapors,  also 
it  occasions  them  to  move  more  slowly,  thus  caus- 
ing them  to  remain  longer  in  contact  with  the 
cooling  surface.  The  worm  condenser  is  shown 
in  Fig.  1  and  Fig.  2.  To  receive  wood  distillates 
all  that  is  necessary  is  to  attach  some  form  of  gas 
trap  or  separator,  such  as  shown  in  Fig.  12,  so 
as  to  separate  the  gas.  The  tank  shown  is  for  the 
containing  water  and  should  have  an  inlet  pipe  at 
the  bottom  for  cold  water  and  an  overflow  pipe 
at  the  top  for  the  hot  water  to  escape.  Several 
forms  of  pipe  coolers  are  used  in  the  various  indus- 
tries. One  form  is  seen  in  artificial  ice  factories 
where  several  rows  of  pipes  are  connected  with 
return  bends  and  a  perforated  pipe  above  all  from 
which  a  stream  of  water,  the  entire  length  of  the 
pipe,  falls  upon  each  pipe  in  its  descent.  This 
v/ater  is  cold  at  the  top  layer  of  pipes,  but  as  it 
reaches  the  bottom  it  becomes  quite  warm,  finally 
falling  to  the  floor  or  ground  and  running  off.  In 
such  an  apparatus  the  liquid  or  vapors  should  pre- 


ferably come  in  at  the  bottom  and  come  out  at 
the  top.  Such  an  apparatus  is  not  good  for  va- 
pors, although  suitable  for  cooling  liquids.  With 
vapors  the  condensed  matter  would  cause  back 
pressure  unless  the  vapors  came  in  at  the  top,  in 
v;hich  latter  case  they  would  not  be  thoroughly 
cooled  unless  a  great  amount  of  water  was  used. 

In  the  gas  works  we  find  the  pipes  placed  verti- 
cally instead  of  horizontally  and  cooled  only  by 
air.  Provision  is  made  for  the  collecting  of  the 
condensed  products  by  means  of  a  partitioned  box 
at  the  bottom.  In  this  way  the  condensed  product 
falls  into  the  box  and  the  gas  passes  on  to  the 
next  chamber  following  the  pipe,  and  any  other 
further  condensed  product  is  separated  in  like 
manner  until  the  gas  escapes  from  the  condenser. 

Another  form  similar  to  what  was  used  at  a  wood 
distilling  plant  at  New  Orleans  was  of  the  style 
shown  in  Fig.  13.  This  is  sometimes  called  a  box 
cooler  because  of  its  outward  shape,  but  should 
Le  distinguished  from  the  box  condenser  before 
described.  In  the  distillation  of  wood  various  tar- 


D 


FIG    13— BOX    CONDENSER. 
A — From  retort. 
B — Water  overflow. 
C — Gas  to  furnace. 
D— Water  inlet. 
E — Gas  trap. 
F — Goose-neck   discharge. 


36 


THE.  UTILIZATION  OP  WOOD    WASTE     BY     DISTILLATION. 


ry  matters  form  which  sometimes  adhere  to  the 
pipe  and  cannot  be  washed  out.  One  can  easily 
understand  that  an  ordinary  worm  condenser 
v.'ould  be  troublesome  if  it  should  have  occasion 
to  block.  To  avoid  this  the  arrangement  shown 
iu  Fig.  13  is  made.  First,  the  pipe  leading  from 
the  retort  is  connected  with  a  T  instead  of  a 
direct  elbow  and  one  end  fitted  with  a  cap  or 
flanged  head  that  can  be  removed  for  cleaning 
purposes.  Then  each  return  bend  is  on  the  out- 
side of  the  box  and  being  flanged  to  the  ends  of 
the  pipe  protruding  through  the  box  they  can 
be  readily  taken  off  for  cleaning  purposes. 
Of  course,  proper  stuffing  boxes  should  be  made 
for  the  ends  of  the  pipe,  so  that  the  pipes  can  ex- 
pand and  at  the  same  time  no  water  escape  where 
the  pipe  goes  through  the  box.  As  in  the  worm 
condenser  the  pipes  can  be  gradually  made  small- 


er toward  the  discharge  end.  Sometimes  the  first 
pipe  is  subdivided  into  two  connecting  pipes  so 
as  to  give  the  condenser  more  cooling  surface 
v.here  the  vapors  first  come  in  contact  with  it.  At 
the  outlet  the  usual  gas  trap  should  be  placed.  In- 
stead of  having  the  pipes  directly  under  one  anoth- 
er they  can  be  placed  with  alternate  pipes  to  one 
side  and  only  a  little  lower,  thus  making  the  box 
wider  and  not  so  deep.  It  is  best  to  give  each 
pipe  a  rather  sharp  decline  so  that  the  condensed 
products  will  readily  flow  out. 

Counter  Current  Pipe  Cooler. — Instead  of  the 
pipes  being  placed  in  a  box  as  in  the  above  form, 
each  pipe  may  be  surrounded  with  a  larger  size 
pipe  containing  the  cooling  water.  These  water 
pipes  are  connected  with  one  anotner  at  alternate 
ends.  The  return  ends  are  not  covered,  but  remain 
exposed  as  in  the  box  cooler  so  that  they  can  be 


FIG.  14— DOUBLB  PIPE  COUNTBR  CURRENT  CONDENSER. 


THE   UTILIZATION   OF   WOOD    WASTE     BY    DISTILLATION. 


37 


readily  taken  off   and  the  pipes  cleaned.     Where 
ncid   vapors   are   condensed  the  inner  pipe   should 
be   of   copper,   but   the   outer  pipe   containing,  the 
•water  is  usually  of  iron.     Such  a  cooler  is  shown. 
In  Fig.  14  and  the  connection  in  Fig.  15. 

Tubular  Condensers. — It  has  been  noticed  that 
small  tubes  are  more  efficient  as  cooling  agents 
than  large  ones  in  proportion  to  their  carrying 
capacity.  This  is  due  to  the  fact  that  the  cooling 
surface  is  actually  greater,  and  also  the  rapidity 
with  which  the  vapors  can  be  brought  into  con- 
tact with  the  cool  surface.  A  tubular  condenser  is 
rcore  complicated,  has  more  chances  to  leak  and 
has  the  further  disadvantage  that  as  usually  con- 


FIG  15. 

A — Water. 

B — Condenser  pipe. 


siructed  a  large  part  of  the  cooling  surface  is  not 
brought  in  contact  with  the  cooling  water. 

This  latter  condition  is  purposely  made  so  that 
the  tops  can  be  easily  removed,  but  it  is  easy 
enough  to  cover  them  with  water  if  need  be. 

A  tubular  condenser  as  used  in  a  steam  process 
plant  is  shown  in  Fig.  16.  This  form  has  been  in 
use  in  the  hardwood  distillation  for  some  time. 
Other  forms  are  used,  modified  only  to  enable 
them  to  be  cleaned  out  better.  Interested  parties 
should  obtain  the  views  of  the  makers.  • 


In  making  this  form  of  condenser  the  outer  shell 
should  be  made  of  tank  steel  and  fitted  with  suit- 
able inlet  and  outlet  pipes.  The  inner  part  should 
be  of  copper  and  should  be  well  braced  in  the 
tank  and  rest  upon  a  small  support  in  order  to 
allow  the  water  to  get  under  it  and  cool  the  bot- 
tom chamber.  The  top  is  in  the  form  of  a  dome 
end  is  fitted  with  a  head  that  can  be  removed 
and  tightened  on  by  means  of  the  yoke  and  wheel 
shown.  In  larger  sizes  wing  nuts  could  be  placed 
Rroimd  the  circumference  and  thus  draw  the  edges 
together.  The  tubes  should  be  well  beaded  into  a 
bronze  or  brass  plate  on  both  ends,  these  ends 
forming  the  top  and  bottom  respectively  of  the 
lower  and  upper  chambers.  The  upper  chamber 
or  dome  should  be  fitted  with  a  large  opening  for 
the  inlet  of  the  vapors  and  the  bottom  chamber 
fitted  with  an  outlet  for  the  condensed  vapors  and 
a  hand  hole  (not  shown)  for  cleaning  cut  pur- 
poses. These  connections  should  pass  through  suit 
able  stuffing  boxes  to  prevent  the  water  from  com- 
ing out  of  the  tank.  A  gas  separator  should  fol- 
low the  condenser.  The  upper  dome  should  be  of 
sufficient  size  to  distribute  the  vapors  as  they  come 
In  without  causing  back  pressure  and  the  tubes 
should  be  of  sufficient  size  and  number  for  the 
same  reason.  In  fact,  it  would  be  better  to  have 
them  of  greater  capacity  so  that  when  the  vapors 
enter  if  they  should  be  under  pressure  they  would 
naturally  have  a  tendency  to  expand  and  thus  re- 
duce the  pressure  and  help  relieve  the  retort.  Other 
forms  of  condensers  could  be  used  and  different 
positions  might  be  given  those  described,  a  hori- 
2ontal  tubular  condenser  being  better  for  con- 
densing engines,  but  usually  to  cool  the  vapors 
ficm  the  wood  it  is  better  to  have  them  enter  at 
the  top  and  discharge  at.  the  bottom  as  is  the 
case  with  vertical  condensers. 

In  regard  to  the  size  of  the  various  condensers 
as  a  general  rule  150  square  feet  of  cooling  sur- 
face is  sufficient  for  each  cord  with  water  at  the 
usual  average  temperature  found  in  the  South  and 
the  present  rate  of  distilling. 

The  following  points  are  to  be  considered  in 
estimating  the  size:  1st,  the  volume  of  vapors 


38 


THE   UTILIZATION   OF  ' WOOD    WASTE     BY     DISTILLATION. 


B 


FIG    1C— TUBULAR   CONDENSER. 

A— Water  inlet. 
B — To  gas   trap. 


THE   UTILIZATION   OF   WOOD    WASTE     BY     DISTILLATION. 


39 


tc  be  condensed  in  a  given  time.  2nd,  the  rate 
ol  speed  at  which  they  are  flowing.  3rd,  the  tem- 
perature of  the  cooling  water  and  the  kind  of  ma- 
terial of  which  the  cooling  surface  is  made.  The 
volume  of  the  vapors  can  be  determined  by  multi- 
plying the  number  of  cubic  feet  of  products  expect- 
ed in  a  given  time  by  1700.  If  30  cubic  feet  of 
material  were  distilled  in  24  hours  then  1 1-4  cubic 
feet  would  be  the  average  distilled  in  one  hour; 
this  multiplied  by  1700  equals  212,500  cubic  feet  ol 
gases  or  vapors.  In  addition  to  this  there  would  be 
not  over  20,000  cubic  feet  of  gas  at  212°  Fah.,  if 
the  destructive  process  is  used.  With  this  latter 
process  the  temperature  reaches  900°,  consequent- 
ly the  gas  which  is  produced  at  that  temperature 
is  equal  to  over  twice  the  volume  at  212°,  so  the 
entire  volume  to  be  disposed  of  would  be  at  least 
232,000  multiplied  by  two,  or  930,000  feet. 

To  cool  this  product  no  general  rule  can  be  made 
that  would  be  more  than  a  rough  approximate. 
With  the  steam  process  it  is  simply  a  matter  of 
condensing  so  much  steam  at  a  given  temperature 
and  pressure.  The  calculation  is  based  on  a  math- 
ematical basis  and  is  estimated  by  the  number  of 
heat  units  absorbed  by  copper  surfaces  under  given 
conditions.  The  temperature,  specific  heat,  specific 
gravity,  volume,  etc.,  of  the  vapors  must  be  known, 
the  temperature  of  the  cooling  water  at  its  en- 
hance and  exit  are  also  necessary  factors.  1 
might  be  considered  that  it  would  follow  the  same 
rules  of  cooling  water  with  water,  but  such  is  not 
the  case. 

Kent  gives  it  that  "whilst  400  to  600  units  of  heat 
are  transmitted  from  water  to  water  through  iron 
plates  per  degree  of  difference  of  temperature  per 
hour,  air  or  other  dry  gas  transmits  only  about  2  to 
o  units  according  as  the  surrounding  air  is  at  rest 
or  in  movement.  In  a  locomotive  boiler  where 
radiant  heat  was  brought  into  play  17  units  of 
heat  were  transmitted  through  the  plates  of  the 
fire  box  per  degree  of  difference  of  temperature 
per  square  foot  per  hour. 

A  more  detailed  discussion  of  the  heating  and 
croling  of  vapors  and  liquids  will  be  given  under 


the  description  of  the  heating  of  steam  stills  and 
the  cooling  of  vapors. 

The  rate  of  speed  of  the  vapors  in  reality  regu- 
lates the  volume  of  the  vapors  impinging  upon  a 
given  surface  per  hour,  so  might  mean  the  same  as 
the  first  item  mentioned.  However,  as  it  is  neces 
sary  for  the  vapors  to  touch  the  surface  before 
being  condensed  it  can  be  conceived  how  in  ; 
large  cooling  pipe  a  large  amount  of  vapor  could 
be  in  the  middle  of  the  pipe  without  being  cooled 
and  any  short  sudden  pressure  would  force  this 
cut  uncondensed.  For  this  reason  it  might  be  ad- 
visable to  make  them  just  a  little  longer  than  oth- 
erwise. 

Tiie  temperature  and  amount  of  cooling  water 
used  also  affects  the  size  of  the  condenser  needed. 
Where  the  water  is  "old  tne  condenser  wouid  be 
smaller,  and  where  plenty  of  water  is  to  be  had 
(heaply  it  could  be  used  to  help  a  small  condenser 
by  rapid  circulation.  Where  there  is  such  a  vast 
difference  between  the  vapors  and  the  cooling  wa- 
ter, water  at  212°  acts  as  a  cooling  agent  at  the 
top  of  the  condenser.  It  is  better  to  have  the 
condenser  of  such  a  length  that  at  the  required 
rate  of  distillation  the  water  will  overflow  at  about 
200°  Fah.  It  is  cheaper  to  have  a  large  condenser 
than  to  have  to  pump  water. 

The  thickness  and  nature  of  the  metal  influences 
the  efficiency  of  the  condenser.  M.  Peclet  found 
that  with  perfectly  clean  metal  the  quantity  of  heat 
transmitted  is  inversely  proportional  to  the  thick- 
ness. Many  say  that  it  makes  no  difference  what 
the  thickness  is  as  far  as  the  transmitting  of  heat 
i^  concerned,  but  that  it  is  only  necessary  to  make 
tbe  coils  or  tubes  thick  enough  for  strength  and 
ligidity.  Copper  pipe  1-16  inch  thick  is  much  used 
for  the  purpose  in  pipes  and  tubes,  but  for  the  large 
condensers  greater  thickness  is  required  and  for 
tube  plates  3-8  inch  or  more. 

In  tubular  condensers  the  tubes  are  about  1^ 
inches  to  2  inches  in  diameter,  and  6  to  10  feet 
in  length,  and  from  3-32  to  5-32  thick.  In  arrang- 
ing them  in  the  plates  it  is  necessary  to  have  them 
far  enough  apart  so  as  not  to  weaken  the  plate 
itself  and  also  to  facilitate  construction. 


40 


THE   UTILIZATION   OF  WOOD    WASTE     BY     DISTILLATION. 


Receivers  and  Storage  Tanks. — In  the  destruc- 
tive distillation  and  in  the  other  processes  for  ob 
taining  turpentine  and  tar  from  wood  some  method 
must  be  used  to  separate  the  oily  matter  from  the 
watery  portion.  The  condensers  discharge  their 
products  either  directly  into  a  tank  of  some  de- 
scription, or  into  a  pipe  leading  to  such  a  recep- 
tacle. When  the  first  distillate  from  pine  wood 
comes  over  the  product  consists  of  water  and  oil 
when  steam  is  used  and  slightly  acid  water  and 
oil  when  destructively  distilled.  Upon  standing 
this  mass  separates  in  two  layers,  the  oily  matter 
en  top  and  the  water  below.  All  that  is  necessary 
to  separate  them  is  to  draw  off  the  water  from 
below  or  to  let  the  oil  overflow.  The  same  rule 
applies  to  the  tarry  products  also,  only  we  find  the 
acid  water  often  on  top.  This  liquor  usually  has 
to  stand  a  long  time  before  it  can  be  completely 
separated  so  it  is  desirable  to  have  several  tanks 
for  receiving,  allowing  the  others  to  settle  while 
one  is  filling  up. 

In  the  South  wooden  tanks  are  not  of  much  ser- 
vice for  collecting  turpentine  in  any  form.  As  the 
oil  from  the  retort  contains  water  it  would  soften 
any  glue  that  might  be  ired  to  keep  them  from 
leaking.  An  iron  or  eartherware  tank  is  the  only 


suitable   receptacle      for     the     crude     turpentine. 

For  tar  and  acid  iron  is  not  good  and  wood  will 
leak,  but  as  the  acid  products  are  of  comparatively 
15ttle  value  wooden  vessels  can  be  used,  provided 
ihey  are  furnished  with  suitable  bolts  for  tighten- 
ing the  bands  on  the  tank.  For  discharge  cocks 
large  wooden  beer  taps  are  very  suitable.  Some- 
times large  pits  are  made  in  the  ground  and  the 
sides  boarded  up  and  pitched.  These  are  all  called 
settling  vats  or  pits. 

All  that  is  necessary  in  these  receptacles  is 
to  have  suitable  pipes  and  valves  t&  draw  off  the 
separated  liquors  or  to  pump  or  blow  them  out  into 
the  refining  apparatus. 

It  is  advisable  to  have  collecting  tanks  for  each 
crude  product  for  at  least  a  week's  run.  This  is 
especially  true  with  regard  to  the  tarry  liquors, 
as  the  longer  they  are  allowed  to  settle  the  better 
the  separation.  In  this  case  seven  tanks  sufficient 
to  hold  a  day's  run  should  be  used,  or  better,  seven 
tanks  each  twice  the  capacity  of  the  tar  still  would 
be  suitable.  By  this  means  the  liquor  in  the  first 
tank  would  have  settled  for  seven  distilling  pe- 
riods and  the  water  and  acid  (both  together  equal 
to  about  one-half)  could  be  drawn  off  and  the  re- 
mainder put  into  the  still. 


CHAPTER  V. 

REFINING   METHODS. 


The  crude  materials  or  distillates  having  been 
collected  in  the  receptacles  just  described,  it  is  nec- 
essary to  treat  them  in  some  manner  in  order  to 
make  them  merchantable. 

The  crude  turpentine  consists  largely  of  turpen- 
tine oil,  resin  oil,  resin  and  more  or  less  of  the 
gummy  and  extractive  matters  to  be  found  in  wood. 
As  generally  produced,  one  or  two  distillations  will 
sufficiently  refine  the  turpentine  and  leave  it  white 
and  pleasant  smelling.  However,  in  some  cases 
it  is  better  to  treat  with  some  kind  of  alkali,  which 
will  remove  the  gums  before  distilling.  Some  oper- 
ators put  caustic  soda  solution  directly  into  the 
still,  but  this  is  not  to  be  recommended,  as  a  re- 


sinate  of  the  alkali  is  found  when  resin  oil  is  pres- 
ent, and  the  steam  used  in  refining  will  decompose 
it  toward  the  latter  stages  of  the  distillation  and 
distill  it1  over  into  the  refined  oil,  and  thus  make  it 
gummy  and  slow  drying.  If  the  distillation  is 
stopped  at  this  point  all  the  turpentine  is  not  dis- 
tilled and  the  yield  is  less.  Lime,  when  used, 
should  be  put  into  the  still,  as  it  forms  a  compound 
not  easily  separated  from  the  oil.  Although  lime 
will  take  out  resin  and  is  cheap,  it  is  not  very 
suitable  as  a  refining  agent.  It  takes  a  long  time 
to  act  and  when  put  in  the  still  direct  it  causes  a 
coating  on  the  walls  and  steam  pipes,  which  is 
not  only  difficult  to  remove,  but  makes  it  necessary 


Of- 


FIG.  17—750  GALLON  STEAM  HEATED  TURPENTINE  REFINING  STILL. 
A — Charging   bung.  B — Steam  jet. 

C — Detail    of   jet.  D — Vacuum   valve. 

E — Discharge   valve.  F — Exhaust   from   coil. 

G— Boiler  connection  between  head  and  still. 


42 


THE   UTILIZATION   OF  WOOD    WASTE     BY     DISTILLATION. 


to  use  more  steam  in  the  closed  coil,  as  the  heat 
does  not  penetrate  well  through  the  coating.  Caus- 
tic soda  seems  to  be  the  best  chemical  for  purify- 
ing. A  weak  solution  answers  the  purpose  and 
should  be  thoroughly  mixed  with  the  crude  oil. 
This  is  best  done  by  stirring  with  cold  compressed 
air  or  by  means  of  any  mechanical  stirrer  used  in 
the  arts.  This  mixture  should  be  allowed  to  settle 
and  the  lye  drawn  off  at  the  bottom  as  closely  as 
possible,  then  water  added  and  the  lye  washed  out 
by  mixing  and  settling  with  the  water.  The  resi- 
dual oil  should  then  be  pumped  into  a  copper  or 
iron  still  and  distilled  by  means  of  steam.  Such  a 
steam  still  is  shown  in  Fig.  17.  This  still  is  so 
arranged  that  the  crude  oil  can  enter  at  A.  A 
steam  scroll  composed  of  a  closed  copper  pipe  is 
shown  on  the  bottom;  close  to  it  at  B  is  a  perforated 
cross  made  of  copper  pipe  and  shown  in  detail 
at  C.  This  allows  sufficient  live  steam  to  enter 
to  thoroughly  stir  the  contents  of  the  still.  Water 
is  admitted  through  A  at  the  same  opening  as  the 
crude  oil.  A  vacuum  valve  is  placed  at  D  to  pre- 
vent any  collapse  by  a  sudden  cooling.  At  the  bot- 
tom are  two  outlets,  the  one  at  B  for  the  residue  of 
the  distillation  to  be  discharged,  and  the  one  at  F 
to  allow  the  condensed  steam  to  escape  by  connec- 
tion to  a  steam  trap,  or  otherwise.  To  make  the 
cap  or  head  tight  it  is  bolted  onto  the  still  as 
shown  at  G.  This  is  connected  with  an  ordinary 
worm  condenser  or  tubular  condenser,  or  the  other 
forms  mentioned.  The  still  is  an  ordinary  750- 
gallon  steam  still. 

In  designing  a  still  it  can  be  readily  seen  that 
the  greater  the  diameter  the  more  evaporating  sur- 
face, consequently  we  find  that  some  makers  of 
stills  make  them  of  very  large  diameter  and  not 
very  high.  On  the  other  hand,  with  steam  stills 
some  prefer  to  have  the  body  of  the  still  of  the 
same  height  as  the  diameter.  The  thickness  varies 
with  the  maker;  the  McMillan  Bros.  Co.,  of  Mobile, 
Ala.,  make  the  top  of  a  2,000-gallon  still  of  No. 
12  Stubb's  gauge  copper,  the  bottom  of  No.  10  and 
the  sides  of  No.  13.  A  still  of  this  size  furnished 
with  100  lineal  feet  of  2-inch  tubing,  No.  13  gauge, 
with  the  brass  cross  shown  in  Fig.  17,  and  all  the 


necessary  connections  will  be  supplied  for  $800  to 
$900,  according  to  the  number  of  attachments  and 
extra  work. 

When  heating  stills  by  steam  coils  to  get  the 
best  effect,  the  coil  must  be  drained.  This  is  done 
by  means  of  a  steam  trap,  an  apparatus  which  holds 
the  steam  back  and  at  the  same  time  allows  the 
water  to  escape.  As  condensed  water  is  forming 
along  the  entire  length  of  the  coil  the  diameter  of 
the  coil  should  be  rather  large,  so  as  to  be  able  to 
carry  the  water  to  the  steam  trap  without  letting 
the  water  fill  up  part  of  the  coil,  thus  preventing 
the  full  action  of  the  steam.  Be  sure  to  have  a 
steam  trap  large  enough  to  carry  off  the  water.  In 
working  with  a  steam  trap  the  water  condensed  in 
the  coil  under  pressure  when  it  escapes,  will  boil 
and  cause  steam  when  exposed  to  the  atmospheric 
pressure,  thus  causing  one  to  think  that  the  trap 
is  leaking  steam.  The  only  thing  necessary  with  a 
good  steam  trap  is  to  have  it  large  enough. 

The  size  of  the  coil  and  trap  "can  be  determined 
beforehand  by  considering  the  contents  of  the  still 
to  be  nothing  but  water.  This  we  can  do  because 
the  temperature  of  a  mixture  of  water  and  turpen- 
tine, such  as  is  usually  distilled,  does  not  have  a 
higher  boiling  point  than  does  water.  Also,  the 
specific  heat  of  turpentine  of  a  density  of  .872  sp. 
gr.  is  .472,  water  being  1,  so  being  less  than  water, 
one  would  be  on  the  safe  side  to  consider  it  as 
water. 

We  will  not  go  into  the  scientific  details  of  the 
causes  and  principles  of  heating  and  cooling,  but 
confine  ourselves  to  a  brief  consideration  of  the  sub- 
ject. The  effectiveness  of  heating  liquids  by  means 
of  steam  in  a  closed  coil  depends  upon  many  con- 
ditions. The  coil  should  be  drained  as  well  as 
possible  so  as  to  get  the  full  effect  of  the  steam 
at  the  temperature  and  pressure  used.  The  circu- 
lation of  the  liquid,  the  thickness  of  the  coil  and  the 
presence  or  absence  of  a  deposit  on  the  coil  affect 
the  efficiency.  The  difference  in  temperature  be- 
tween steam  in  the  coil  and  the  liquid  to  be  heated 
ako  affects  the  time  of  transmission  to  a  large 
extent,  the  greater  the  difference  the  more  heat 


THE   UTILIZATION   OF   WOOD    WASTE     BY     DISTILLATION. 


43 


units  per  degree  difference  of  temperature   being 
transmitted. 

The  element  of  time  enters  into  the  considera- 
tion of  the  subject,  for  no  matter  how  hot  the 
steam  may  be  it  will  take  some  time  to  heat  the 
liquid.  The  time  required  depends  upon  the  sup- 
ply of  steam  and  the  rate  of  transmission  is  usually 
expressed  by  the  number  of  British  thermal  units 
(B.  T.  U.)  transmitted  from  the  hot  side  to  the 
cool  side  per  degree  Fahrenheit  of  temperature 
difference  per  square  foot  per  hour.  A  B.  T.  unit 
is  the  heat  required  to  raise  one  pound  of  water 
1  degree  Fah.,  the  standard  being  the  degree  from 
39.1  degree  Fah.  to  40.1  degrees  Fah. 

Experimental  work  indicates  that  copper  coils  are 
more  effective  than  those  of  other  metals  in  com- 
mon use,  and  for  these  certain  experimenters  found 
250  B.  T.  units  were  transmitted  per  degree  Fah. 
difference  in  temperature  per  square  foot  per  hour 
when  heating  cold  water,  and  M.  Peclet  found  that 
tc  evaporate  at  212  degrees  Fah.  as  many  as  935 
B.  T.  units  were  transmitted  per  degree  of  differ- 
ence, due  probably  to  the  more  rapid  circulation  of 
the  water.  Other  experimenters  find  different' 
amounts,  one  testing  steam  feed  water  heaters  ob- 
serving that  3G8  B.  T.  U.  were  transmitted  up  to 
212  degrees  Fah.,  and  6GO  B.  T.  U.  at  212  degrees 
Fah.,  probably  with  a  steel  coil,  although  not  stated. 
Our  problem  in  a  still  is  confined  to  heating  water 
(water  and  oil)  by  means  of  steam,  hot  gases  act- 
ing differently.  If  we  take  a  high  rate  of  transmis- 
sion our  coils  would  be  made  small  and  steam  trap 
large,  and  when  we  came  to  condensers  the  worm  or 
tubes  would  be  small  and  our  water  supply  large. 
If  for  any  reason  the  coil  did  not  work  perfectly 
there  would  be  a  bad  condition  of  affairs,  as  one 
could  not  change  the  coils  readily.  By  taking  a  low 
rate  of  transmission  and  one  was  disappointed  in 
the  results  of  transmission  and  it  was  higher,  then 
all  that  would  be  necessary  to  do  would  be  to  in- 
crease the  size  of  the  steam  trap  and  to  increase 
the  supply  of  cooling  water  to  the  condensers, 
something  which  can  be  readily  done. 

The  above  experiments  on  the  transmission  of 
heat  were  made  with  clean  coils.  Those  who  are 


obliged  tc  use  foul  coils,  as  in  the  case  wnen  dis- 
tilling resinous  oils,  find  that  about  one-third  of  the 
rate  of  transmission  given  above  is  the  proper 
working  rate.  In  evaporating  sugar  solutions 
the  water  from  which  would  be  more  diffi- 
cult to  distill  than  in  the  case  under  consideration, 
from  265  to  376  B.  T.  U.  are  transmitted. 

One  would  be  safe  in  averaging  300  B.  T.  units 
per  degree  Fah.  difference  in  temperature  per 
square  foot  per  hour,  both  for  heating  the  liquor  to 
the  boiling  point  and  distilling.  In  addition  to  heat- 
ing the  water  to  be  distilled  the  cooling  effect  of 
the  air  on  the  surface  of  the  still  itself  must  be 
overcome  by  the  heat  of  the  coil  in  order  to  force 
the  vapors  high  enough  in  the  pipe  to  where  it 
bends  to  the  condenser.  The  influence  of  the  air  is 
equal  to  about  1.7327  B.  T.  units  per  degree  of  differ- 
ence in  temperature  (Fah.)  between  the  contents  of 
the  still  and  the  outside  air,  (the  extremes  being 
taken  for  each  square  foot  surface  per  hour  when 
the  still  is  of  copper,  and  about  1.438  B.  T.  units  for 
iron).  This  includes  all  the  surface  of  the  still  and 
vapor  pipe  to  the  point  at  which  the  pipe  turns  to 
the  condenser. 

On  an  average  one  gallon  of  water  per  square 
foot  per  hour  should  be  evaporated  by  an  iron  coil 
and  about  three  gallons  by  a  copper  coil,  and  often 
more. 

The  size  of  the  steam  trap  is  calculated  in  a  re- 
verse manner,  the  cooling  effect  of  the  water  evap- 
orated causes  a  certain  amount  of  steam  to  be  con- 
densed, this  being  based  on  the  B.  T.  units.  The 
steam  trap  should  be  more  than  large  enough  to 
carry  away  this  water. 

A  concrete  example  of  this  calculation  can  be 
made  with  the  750-gallon  still  illustrated.  Sup- 
pose one  wishes  to  distill  500  gallons  in  ten  hours, 
what  would  be  the  size  of  the  coil  and  steam  trap, 
the  steam  being  supplied  at  300  degrees  Fah.  tem- 
perature and  53  pounds  pressure?  Take  the  weight 
of  a  gallon  of  water  at  8. 34  @  62  degrees,  or  better, 
perhaps,  8 1-3  pounds.  We  then  have  about  4,167 
pounds  of  water  to  distill.  If  it  takes  1  B.  T.  U. 
to  raise  one  pound  of  water  1  degree  Fah.,  it  would 
take  4,167  B.  T.  units  to  raise  the  4,167  pounds  1 


THE   UTILIZATION   OF  WOOD    WASTE     BY     DISTILLATION. 


degree.  If  the  water  was  at  60  degrees  to  bring  it 
to  212  degrees  Fah.,  or  the  boiling  point,  there 
would  be  152  degrees  to  raise  the  4,167  pounds  of 
water  with  4,167  B.  T.  units  for  each  degree.  This 
would  equal  4167x152,  or  633,384  B.  T.  units  ex- 
pended to  bring  the  water  to  the  boiling  point.  Con- 
sidering no  pressure  (although  there  may  be  a  lit- 
tle), it  is  necessary  to  heat  further  only  sufficiently 
to  evaporate  the  water.  When  we  evaporate  water 
the  latent  heat  must  be  considered  and  instead  of 
1  B.,  T.  U.  for  each  pound  to  raise  it  one  degree 
it  will  be  found  that  each  pound  of  water  absorbs 
about  966  B.  T.  units  and  the  temperature  doesn't 
change.  Then  to  evaporate  the  water  we  must 
supply  in  addition  to  the  heat  necessary  to  bring 
it  to  the  boiling  point  4167x966,  or  4,025,322  B.  T. 
units,  which,  -  together  with  the  633,384  used  in 
heating  the  water  makes  a  total  of  4,658,706  B.  T. 
units  to  be  supplied  in  ten  hours,  or  465,871  B.  T. 
units  per  hour.  (Plus  allowance  for  air  cooling.) 

The  temperature  in  the  coil  is  300  degrees  Fah. 
and  the  water  60  degrees,  the  average  water  136  de- 
grees, a  difference  of  164  degrees.  For  each  de- 
gree, according  to  previous  decision,  300  B.  i\  units 
are  transmitted  per  square  foot  per  hour,  or  164x 
300,  or  49,200  B.  T.  units  per  square  foot  per  hour 
under  the  given  conditions.  The  total  to  be  sup- 
plied in  one  hour,  not  counting  the  cooling  effect 
of  the  air,  is  465,871  B.  T.  units,  so  465,871  divided 
ly  49,200  equals  about  9.48  or  9}£  feet,  nearly.  To 
find  the  size  of  steam  trap  it  will  be  found  thai 
only  the  latent  heat  of  the  steam  is  used  in  heating 
with  a  coil  using  a  trap.  The  latent  heat  of  steam 
at  53  pounds  or  300  degrees  Fah.  is  about  904  B.  T. 
units,  and  to  lose  465,871  B.  T.  units  in  one  hour 
it  would  take  465,871-^904,  or  about  515  pounds,  of 
condensed  steam  per  hour.  The  weight  of  a  gallon 
of  water  at  that  temperature  is  about  7.7  pounds, 
so  the  steam  trap  should  have  a  carrying  capacity 
of  about  67  gallons  per  hour.  It  will  be  noticed  that 
this  amount  is  almost  seven  times  the  number  o\ 
square  feet  in  the  coil.  The  heat  in  the  condensed 
water  passing  through  the  steam  trap  should  be 
utilized,  but  it  never  is.  To  use  this  heat  in  the  still 
the  coil  would  have  to  be  large  enough  to  condense 


all  the  steam  to  212  degrees  Fah.,  and  not  use  the 
steam  trap,  a  practice  that  would  not  succeed  well. 
It  is  better  to  make  the  trap  a  size  larger.  An  im- 
portant point  to  consider  is  the  size  of  the  steam 
pipe.  This  should  be  large  enough  to  supply  suffi- 
cient steam  to  heat  the  coil  sufficiently.  There 
is  no  use  in  having  plenty  of  heating  surface  and 
not  enough  steam. 

Further  discussion  of  this  matter  can  not  be 
given  here.  It  is  a  question  of  steam  practice 
familiar  to  engineers.  Other  vapors  than  steam  act 
differently,  generally  the  rate  of  transmission  being 
much  less.  Fire  gases  act  slowly,  but  their  action 
is  also  quite  well  known. 

Tar  Stills. — At  this  place  will  be  considered 
only  the  stills  necessary  for  removing  the  light  oils 
present  in  the  tar  without  distilling  the  tar  itself. 

The  crude  liquors  containing  acids  and  tannin 
matters  are  very  injurious  to  iron,  so  copper  ought 
to  be  used.  Some  remove  the  organic  compounds 
present,  which  become  dark  when  acted  upon  by 
iron,  by  treatment  before  distilling. 

Another  distinction  is  made  as  to  whether  they 
are  to  be  heated  by  direct  fire  or  not.  In  the  former 
case  they  are  made  of  two  shapes,  one  like  a  coal 
tar  or  paraffine  still,  with  a  diameter  about  as 
great  as  the  height  and  the  bottom  concave  ex- 
tending toward  the  middle  about  one-sixth  to  one- 
third  of  its  height,  so  that  the  fire  will  have  more 
surface;  a  man-hole  is  usually  provided  at  the  top 
and  it  is  also  supplied  with  suitable  mountings 
for  steam  pipe  and  thermometer.  The  other  form  is 
similar  to  a  horizontal  boiler.  In  both  forms  the 
vapor  is  carried  off  at  the  top  similar  to  the  vapors 
from  a  turpentine  still  and  condensed  in  a  similar 
manner. 

The  steam  still  is  the  better  as  it  provides  a 
surer  way  of  controlling  the  temperature  and  pre- 
vents the  tar  from  being  burnt.  This  should  be 
made  in  all  particulars  like  the  turpentine  still  al- 
ready described,  and  if  made  of  copper  will  prove 
tc  be  very  efficient.  The  size,  of  course,  must  be 
proportioned  to  the  product,  as  there  is  much  more 
tar  formed  than  turpentine.  The  heating  coil  is 
only  used  for  heating  the  water  and  driving  off  the 


THE   UTILIZATION   OF   WOOD    WASTE     BY     DISTILLATION. 


45 


oil,  the  tar  not  being  distilled.  These  stills  should 
be  placed  in  such  a  position  that  the  tar  can  be 
readily  drawn  off  into  a  tank.  A  continuous  still 
for  removing  the  oils  from  the  tar  has  not  been 
used,  but  a  simple  one  could  be  very  easily  devised 
for  use  at  a  plant  where  there  was  sufficient  crude 
material  produced. 

Wood  Oil  Still.— The  oil  from  the  tar  still 
:an  be  redistilled  in  a  regular  turpentine  still.  By 
making  it  of  iron  with  a  copper  head  and  worm 
this  oil  can  be  treated  with  caustic  soda  or  other 
chemical,  the  caustic  solution  drawn  off  and  the 
oil  redistilled,  making  it  of  a  very  bright  color. 
When  all  the  turpentine  has  not  already  been  re- 
moved from  the  tar  products  the  first  distillate  of 
the  redistillation  of  this  oil  will  be  practically  white. 
Real  wood  oil  should  not  contain  turp,  but  should  be 
a  mixture  of  ordinary  wood,  red  oil  and  various  dis- 
tillates of  rosin  or  resin  found  in  the  wood. 


Still  Heads. — Several  attempts  have  been 
made  to  rectify  spirits  of  turpentine  produced  from 
wood.  As  ordinarily  produced  wood  turpentine 
contains  some  light  oils  that  it  is  desirable  to  re- 
move to  prevent  its  drying  too  rapidly;  also  a 
heavy  oil  is  to  be  found  which  is  often  carried  over 
with  the  steam  when  the  distillation  is  too  rapidly 
conducted.  To  insure  steady  working  of  the  stills 
several  devices  are  in  use.  Two  of  these  are  shown 
in  Fig.  18.  In  A,  instead  of  a  still  head  like  the 
one  shown  in  Fig.  17,  a  small  pipe  is  carried  up  to 
a  considerable  height  before  turning  to  the  con- 
denser. This  pipe  offers  considerable  cooling  sur- 
face to  the  air,  consequently  quite  a  little  fraction- 
ating can  be  done  with  it.  The  lighter  vapors  can 
be  condensed  first;  then  the  turpentine.  In  B  the 
long  pipe  is  branched  and  pipes  placed  on  each, 
the  lighter  vapors  passing  through  the  upper  one, 
and  when  they  are  all  distilled  the  valve  is  closed 


A 


FIG.  18— STILI.  HEADS. 


OF  THE 

~  i-r-W 


46 


THE   UTILIZATION   OF  WOOD    WASTE,     BY     DISTILLATION. 


and  the  vapors  pass  through  the  branch  to  the 
other  condenser.  At  C  is  practically  the  same  thing 
as  at  B,  except  water  is  placed  around  the  pipe  to 
insure  its  being  sufficiently  cooled.  These  methods 
are  all  crude. 

In  Fig.  19  is  a  more  elaborate  head  designed  to 
be  placed  on  a  retort  condenser;  the  proper  place 
for  it,  however,  would  be  on  a  still. 

It  consists  of  a  tank  A  filled  with  water  by  means 
of  pipe  K  overflowing  through  pipe  R.  The  water 
is  allowed  to  enter  between  the  plates  C.  B.  on  both 


sides,  H  being  merely  a  support.  Each  section  is 
cone-shaped  and  T  is  a  band  running  around  the 
sides  of  each  section  so  as  to  enclose  the  top  and 
bottom  of  the  vessel  and  forms  a  chamber  for  the 
vapors,  thus  enabling  them  to  come  in  contact  with 
the  cool  walls,  B  and  C.  Between  the  walls  B  and  C 
is  a  plate  D,  held  at  one  side  by  the  support  shown, 
and  this  prevents  the  vapors  from  rushing  directly 
out  through  P,  thus  acting  as  a  baffle  plate  to  the 
vapors. 

The  operation  is  as  follows:     The  vapors  enter 


FIG.   19— HEGE'S  PATENT  HEAD. 


THE   UTILIZATION   OF   WOOD    WASTE     BY    DISTILLATION. 


47 


at  U,  pass  up  P,  strike  the  baffle  D  and  roll  back 
under  the  edges  of  D,  which  are  open,  and  then 
continue  above  D  until  they  hit  the  next  P,  and 
so  on.  C  being  on  an  incline  any  vapors  con- 
densed on  surfaces  C,  D  and  B,  cannot  fall  back 
through  pipe  P,  into  the  still,  but  follow  down 
N.  As  originally  designed  "no  valve  was  shown 
at  N,  but  there  should  be  one  there  and  it  should 
remain  closed  until  that  portion  of  the  apparatus 
reaches  the  proper  temperature.  In  this  way  any 
light  oils  condensed  when  still  is  first  started  in- 
stead of  running  out  at  S  in  first  section  to  tank 
intended  for  heavy  oils,  the  increasing  heat  would 
again  vaporize  this  condensed  matter  and  event- 
ually put  it  into  the  section  wherein  it  belongs. 

To  determine  the  proper  temperatures  a  ther- 
mometer should  be  placed  before  the  valve  N  in 
each  section.  Any  vapors  that  do  not  condense  are 
carried  away  at  M.  This  apparatus  has  one  very 
bad  feature  in  that  the  cold  water  comes  in  at 
the  top  and  the  hot  water  is  forced  out  at  the  bot- 
tom. It  might  be  better  to  invert  the  condenser 
and  have  U  connected  with  the  still  just  the  same 
and  have  a  Q  on  the  connecting  pipe. 

A  form  similar  to  the  above  described  condenser 
is  used,  which  permits  the  condensed  vapors  to 
fall  back  into  the  still.  No  water  is  used  and  tem- 
perature regulated  so  that  only  the  light  oils  pass 
through  the  head  and  are  condensed.  After  the 
light  oils  pass  over  a  valve  leading  to  this  still 
tiead  is  closed,  another  valve  opened  leading  to  a 
worm  condenser  and  the  distillation  carried  on  in 
the  usual  manner. 

If,  by  the  use  of  a  still  head,  the  bad  odor  in  the 
turpentine  when  it  is  mixed  with  tar  can  be  re- 
moved, as  it  is  done  to  a  large  extent  by  one  com- 
pany, then  the  regular  hardwood  method  of  dis- 
tillation is  the  best  way  of  handling  the  distilla- 
tion of  wood.  However,  even  the  best  refiners  us- 
ing that  process  leave  a  trace  of  disagreeable  odor 
and  a  light  cast  to  the  oil. 

Alcohol  Stills  and  Acetate  Pans. — The  wood  al- 
cohol from  pine  wood  is  seldom  recovered,  as  the 
yield  is  too  small.  The  yield  of  acetic  acid  in  the 
condensed  liquor  is  also  much  less  than  with  hard- 


wood. In  Germany  alcohol  is  made.  Generally 
three  stills  are  required  to  make  the  refined  alco- 
hol. The  first  one  separates  the  alcohol  and  the 
wood  vinegar,  the  second  for  the  treatment 
with  lime,  and  the  third  for  rectifying.  As 
carried  on  in  the  wood  alcohol  plants  in  the 
North  this  is  as  far  as  the  distillation  goes,  the 
further  rectification  being  done  at  refining  plants 
in  special  column  stills. 

The  acetate  pans  are  usually  flat  sheet  iron  pans, 
like  salt  pans,  and  heated  with  the  waste  gases 
and  by  steam.  The  mixture  is  stirred  to  keep 
from  burning  the  acetate  and  thus  decomposing 
it  into  the  carbonate.  A  more  detailed  descrip- 
tion of  this  process  will  be  given  in  describing  a 
German  process. 

Condensers. — Under  this  head  there  is  nothing 
different  to  describe  than  from  those  connected  to 
the  retort.  In  refining  it  is  not  so  necessary  to 
make  arrangements  for  cleaning  as  the  oil  has  a 
tendency  to  act  as  a  cleansing  agent  itself,  and  as 
no  tar  should  be  allowed  in  the  condenser,  it  is  an 
easy  matter  to  keep  it  clean. 

But  the  sizes  of  condensers  has  been  left  for 
consideration  at  this  place.  With  surface  condens- 
ers on  condensing  engines  one  square  foot  of 
heating  surface  is  allowed  for  every  10.6  Ibs.  of 
steam  condensed.  This  leaves  the  water  at  about 
120°  Fah.,  the  temperature  of  the  hot  well.  In  dis- 
tilling turpentine  it  is  necessary  to  bring  the  con- 
densed material  to  as  low  a  temperature  as  pos- 
sible, in  the  summer  time  to  at  least  100°  Fah. 
Then  in  the  case  of  the  engine  condenser  the  ex- 
hausts enter  under  some  pressure,  whereas  in  dis- 
tilling very  little  pressure  is  developed.  Again,  it 
is  known  that  hot  gases,  such  as  come  from  a 
retort,  do  not  transmit  heat  to  water  as  readily  as 
does  steam,  so  a  suitable  formula  must  be  found 
to  suit  the  case.  In  the  condenser  the  cooling  sur- 
face should  be  as  great,  or  greater,  than  the  sur- 
face of  the  coil  in  the  still  and  should  be  able  to 
condense  all  the  vapors  that  the  still  distills.  No 
allowance  can  be  made  for  the  coating  on  the  coil 
in  the  still,  as  a  coating  also  forms  in  time  on 
the  condenser  surface. 


48 


THE   UTILIZATION   OF  WOOD    WASTE     BY     DISTILLATION. 


It  can  be  considered  then  that  the  copper  sur- 
face of  the  condenser  can  transmit  the  same  num- 
ber of  B.  T.  units  as  the  coil  in  the  still  per  square 
foot.  This  was  taken  at  300  for  each  degree  Fah. 
difference  in  temperature  per  hour. 

Continuing  the  example  given  unaer  stills,  how 
many  square  feet  of  condenser  surface  will  be  nec- 
essary to  condense  500  gallons  of  water  in  ten 
hours  with  the  cooling  water  at  60°?  The  differ- 
ence in  temperature  between  the  vapors  and  the 
mean  of  the  water  is  212-130  or  82  and  the  num- 
ber of  units  transmitted  per  degree  300,  and  for 
82  degrees  24,600  per  square  foot  per  hour.  The 
number  of  pounds  of  vapor  in  ten  hours  was  4,167. 
To'  cool  it  the  latent  heat  would  be  966  B.  T.  units, 
and  the  cooling  from  212  to  60°  equals  152  B.  T. 
units,  or  a  total  of  1,118  B.  T.  units  per  Ib.  and  for 
the  whole  amount  4,167x1,118=4,658,706  B.  T.  U. 
to  be  cooled  in  ten  hours  or  465,871  B.  T.  U.  in  one 
hour,  as  we  found  under  the  first  case  with  stills. 
We  have  then  465,871  B.  T.  U.  per  hour  and  an 
absorption  of  24,600  per  square  foot  per  hour  by 
the  cooling  surface  so  to  absorb  it  all  it  would  take 
465,871  divided  by  24,600,  or  about  19  square  feet. 
This  is  about  twice  the  heating  surface  of  the 
coil  in  the  still,  but  this  ratio  varies  with  the 
initial  pressure  and  temperature  of  the  steam,  the 
higher  the  temperature  the  greater  the  ratio  be- 
tween the  heating  surface  and  the  cooling  sur- 
face. 

The  whole  problem  shows  that  it  depends  upon 
the  amount  of  heat  transmitted  by  the  copper  in 
a  given  time.  In  a  water  heater  this  rate  was  only 
68  B.  T.  U.,  using  steel  tubes,  and  in  condensing 
benzol  vapors  only  10  B.  T.  U.  were  transmitted 
per  hour  per  degree  difference  in  temperature 
for  each  square  foot  of  cooling  surface.  With  a  tar 
still  giving  final  vapors  at  637°  Fah.  only  812  B.  T. 
U.  per  hour  per  square  foot  of  surface  were  trans- 
mitted not  for  each  degree,  but  altogether. 

In  a  retort  condenser  where  there  is  such  a 
large  amount  of  gases  other  than  steam  an  allow- 
ance should  be  made  of  a  total  transmission  of  only 
1,000  B.  T.  U.  per  square  foot  per  hour. 

Condensing  Water. — Knowing  the  square  feet  of 


condenser  surface  required,  multiply  by  the  num- 
ber of  heat  units  transmitted  per  square  foot  per 
hour  and  this  will  be  the  total  number  of  heat 
units  to  be  carried  away  by  the  water.  The  num- 
ber of  heat  units  has  been  calculated  all  along 
on  the  mean  temperature  of  the  water  and  as  the 
experiments  on  transmission  were  made  that  way 
it  is  advisable  to  use  the  mean  temperature  of  the 
water  in  calculating  the  results  on  the  con- 
densers. With  the  cooling  water  it  is  different. 
If  the  water  comes  in  at  60°  and  goes  out  at  200° 
it  is  evident  that  140  B.  T.  U.  are  carried  out  with 
each  pound  of  water,  irrespective  of  the  time  it 
takes  to  get  hot.  The  total  heat  represented  in 
B.  T.  units  per  hour  divided  by  this  difference  in 
temperature  equals  the  number  of  pounds  of  cool- 
ing water  required  per  hour.  In  the  above  case 
there  were  465,871-^-140,  or  3,328  Ibs.  per  hour,  and 
,at  8  1-3  Ibs.  per  gallon  equals  about  399  gallons 
per  hour. 

Storage  Tanks. — By  making  the  first  receivers  of 
condensed  retort  vapors  of  considerable  size  they 
help  out  the  storage  capacity  of  a  plant.  These 
receiving  tanks  have  been  spoken  of  before.  In  ad- 
dition to  these  tanks  others  are  needed  for  the  re- 
fined product.  In  some  plants  arrangements  are 
made  to  have  the  condensers  on  one  floor  of  a 
building  and  the  storage  tanks  beneath  so  that  no 
pumping  is  necessary.  A  pump,  though,  particu- 
larly if  brass-lined,  is  usually  cheaper  than  the  ad- 
ditional floor.  A  common  iron  tank  is  not  suitable 
for  turpentine,  but  a  good  galvanized  tank  or  an 
enameled  tank  are  very  suitable  and  hold  well.  An 
enamel  made  of  white  lead  is  sometimes  used  with 
success,  but  the  best  is  a  glass  enamel  baked  on. 

Galvanized  tanks  are  made  upright  with  a  convex 
bottom — they  are  to  be  preferred.  Glass  enamel 
steel  tanks  are  made  in  horizontal  and  vertical 
positions,  the  former  are  better  to  save  height,  and 
the  latter  easier  to  measure.  They  are  usually 
made  in  sections  composed  of  flanged  rings  and 
these  flanged  rings  bolted  together  form  the  tank. 
Tanks  for  tar  can  be  made  of  ordinary  iron.  The 
first  tar  tank  is  one- of  about  the  capacity  or  twice 
the  capacity  of  the  tar  still.  This  is  used  for  re- 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION, 


49 


ceiving  and  cooling  the  hot  tar  from  the  still. 
When  cool  the  tar  can  be  pumped  to  a  large  stor- 
age tank.  This  large  storage  tank  should  be  set 
on  piers  high  enough  to  permit  barreling  of  the 
tar.  There  should  be  plenty  of  storage  capacity, 
as  the  product  is  likely  to  be  slow  moving. 

Shipping  and  Packages. — For  turpentine  eight- 
hooped  white  oak  barrels,  holding  52  gallons,  are 
of  the  right  kind.  Some  use  six  hooped  oil  bar- 
rels, but  they  are  more  difficult  to  keep  tight. 
The  hoops  should  be  well  driven  and  the  barrels 
glued  on  the  inside.  This  is  done  by  putting  about 
four  or  five  gallons  of  hot  glue  in  the  bung  hole, 
inserting  a  plug  and  rolling  the  barrel  so  that  the 
glue  will  touch  all  the  inner  surfaces.  The  plug 
is  then  taken  out  and  the  barrel  set  on  a  run  to 
drain.  Sometimes  it  is  necessary  to  glue  two  or 
three  times,  using  about  a  pound  or  so  of  glue  per 


barrel.  If  no  water  is  put  in  with  the  turp  the 
barrel  will  remain  tight  for  some  time  if  not  ex- 
posed to  the  sun. 

A  tank  car  is  better  for  shipping  purposes,  as 
it  will  not  usually  lean,  Dut  it  is  not  always  as 
clean.  By  coating  the  cleaned  surface  with  shellac 
it  keeps  the  oil  in  good  condition.  For  tar  second 
hand  oil  barrels  are  much  used.  These  should  be 
thoroughly  repaired  and  coopered  and  preferably 
soaked  before  putting  in  the  tar.  A  tar  barrel  mus 
be  kept  out  of  the  sun  or  it  will  surely  leak  m 
summer  weather.  A  picture  is  here  shown  (Fig. 
20)  of  a  steam  and  destructive  distillation  plant, 
showing  tar  barrels  ready  for  shipment  and  also 
tank  car.  Tar  could  be  shipped  in  tank  cars  to 
great  advantage.  Freight  on  wood  distillates  is 
extremely  high  in  proportion  to  their  value  to  the 
regular  naval  stores. 


FIG.    20— SHIPPING   TURPENTINE  AND  TAR  AT  A  STEAM  AND  DESTRUCTIVE   DISTILLATION   PLANT. 


CHAPTER  VI. 

SPECIAL  COMBINATIONS  OF  APPARATUS  AS  USED  IN  MODERN  PLANTS. 


The  different  pieces  of  apparatus  just  described 
are  used  in  various  combinations  according  to  the 
process  used  in  distilling. 

These  processes  may  be  divided  under  several 
heads,  but  the  best  division  seems  to  be  into  Steam 
Processes,  Steam  and  Destructive  Distillation  and 
Destructive  Distillation.  A  fourth  division  of  Spe- 
cial Processes  might  be  used  to  designate  those 
processes  used  in  destructively  distilling  saw  dust 
and  those  using  rotating  retorts,  also  those  retorts 
which  are  to  be  moved  from  place  to  place  and 
those  comprised  of  conveying  machinery  suitably 
enclosed. 

No  attempt  will  be  made  to  assign  any  relative 
value  to  the  patents.  It  has  been  the  custom  for 
one  man  to  advance  an  idea  and  for  another  to 
patent  it,  so  the  patent  itself  will  be  discussed 
only. 

In  considering  these  patents,  it  is  advisable  to 
understand  something  of  the  composition  of  pine 
wood  and  the  products  of  distillation.  These  will 
be  found  in  detail  in  a  special  chapter  under  that 
head.  Briefly  stated,  however,  the  main  object  of 
the  steam  process  is  to  extract  tne  turpentine, 
while  the  object  of  the  other  processes  is  to  ob- 
tain all  the  products  possible  so  that  the  wood 
may  be  completely  utilized. 

Fat  wood  contains  the  woody  fibre  and  resins 
with  other  substances.  The  resin  content  is  more 
stable  at  a  high  temperature  than  the  woody  fibre, 
so  it  is  necessary  to  consider  only  the  temperature 
that  first  attacks  the  wood  itself.  Cellulose  is  af- 
fected at  320°  Fah.,  but  the  temperature  could  be 
raised  slightly  above  that  without  doing  any  seri- 
ous harm  to  the  products  of  decomposition  and 
distillation.'  To  remove  the  resin  and  leave  the 
woody  fibre  intact,  three  or  four  methods  could  be 
employed.  The  rosin  could  be  dissolved  out  by 
suitable  solvents  and  the  solvent  evaporated.  This 
might  possibly  be  a  good  way  now  that  denatured 


alcohol  is  promised  to  be  cheap,  but  requires  con- 
siderable capital  locked  up  in  the  solvent.  An- 
other way  would  be  to  melt  it  out  by  dry  heat, 
another  by  steam  heat,  another  by  heating  and 
squeezing.  Extraction  and  steaming  would  proba- 
bly be  the  methods  that  produce  the  greater  yields, 
as  a  residue  would  be  left  in  the  other  cases  that 
could  not  be  removed  by  the  method  employed. 

In  the  steam  process  for  removing  the  oils,  the 
first  plants  worked  with  large  pieces  of  wood  which 
were  afterwards  destructively  distilled.  The  steam- 
ing process  thus  employed  was  re-discovered  (?) 
in  this  century  and  extraction  by  this  means  con- 
tinued. However,  a  more  important  discovery 
which  influenced  the  industry  more  than  any  pro- 
cess of  extraction  was  a  means  of  cheaply  com- 
minuting the  wood.  This  machine  is  known  as  the 
"hog."  The  advent  of  this  machine  in  the  busi- 
ness has  made  possible  the  extraction  of  turpen- 
tine from  chipped  wood  in  only  a  small  portion 
of  the  time  previously  required. 

At  first  high  pressure  with  steam  was  used,  but 
the  tendency  has  been  to  gradually  diminish  the 
pressure  until  now  ten  or  fifteen  pounds  is  consid- 
ered the  proper  amount.  The  author  believes  a 
vacuum  is  better,  accompanied  with  sufficient 
steam  heat  to  start  the  oils  from  the  wood.  Under 
atmospheric  pressure  the  oil  contained  in  the  resin 
will  distill  in  presence  of  steam  at  212°  Fah.  It 
seems  to  be  more  a  question  of  volume  of  steam 
rather  than  pressure.  Sufficient  volume  of  steam 
should  be  admitted  to  rapidly  carry  over  the  oil. 

An  experiment  to  determine  the  proper  temper- 
ature of  steam  admitted  for  distillation  when  the 
operation  is  carried  on  at  40  Ibs.  pressure  was 
made  at  the  Massachusetts  Institute  of  Technology 
by  Messrs.  Wiggins,  Smith  and  Walker,  with  the 
result  "that  the  optimum  conditions  for  both  tur- 
pentine and  rosin  -are  an  initial  temperature  of 
175°  C,  followed  by  steam  superheated  to  400° 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


51 


C."  By  this  method  there  is  a  larger  amount  of 
both  resin  and  turpentine  produced.  "Below  170° 
C  the  oil  comes  over  slowly  and  will  ultimately 
cease  to  distill  unless  the  temperature  be  raised. 
If  the  temperature  is  run  above  200°  the  yield 
is  not  improved;  the  turpentine  is  discolored  and 
has  a  burnt  odor.  The  yield  of  resin  appears  to 
be  decreased  with  the  higher  heat,  due  to  the  fact 
that  it  decomposes  and  distills  over  with  the 
turpentine." 

The  above  applies,  of  course,  when  working  at 
40  Ibs.  pressure.  It  shows,  though,  that  a  certain 
amount  of  heat  is  better  than  either  a  higher  or 
lower  temperature,  and  this  amount  of  heat  should 
be  determined  for  different  pressures.  The  loss 
of  resin  at  high  temperatures  may  be  due  to 
decomposition  or  to  actual  distillation.  Resin  un- 
der atmospheric  pressure  can  be  distilled  with  but 
little  decomposition  when  in  vacuo  or  by  means 
of  superheated  steam.  By  using  steam  alone  on 
the  chipped  wood  turpentine  generally  distills  and 
the  resin  remains  in  the  retort  except  that  which 
is  carried  over  with  the  steam. 

When  the  destructive  process  is  used  with  or 
without  steam  a  process  should  be  selected  that 
readily  removes  the  turpentine  from  the  wood 
without  decomposing  the  fibre,  or  some  process 
that  has  a  special  method  of  refining  mixed  dis- 
tillates in  a  suitable  manner.  With  those  drawing 
out  the  turpentine  first,  the  apparatus  used  should 
be  one  that  easily  removes  the  turpentine  and 
then  decomposes  the  remaining  wood  at  the  least 
expense  for  fuel  and  at  the  same  time  with  the 
least  damage  to  the  retort.  When  the  turpentine 
is  removed  the  wood  is  of  the  same  bulk  and  us- 
ually dry  and  in  good  condition  for  destructive 
distillation.  As  the  distillation  progresses  the  bulk 
of  the  residue  becomes  gradually  smaller,  so  those 
processes  that  heat  from  the  top  only  are  at  a  dis- 
advantage, for  when  the  heat  snould  be  greatest 
the  material  distilling  is  falling  away  from  the  heat 
instead  of  towards  it  as  it  should.  In  most  cases 
this  disadvantage  could  be  overcome  by  having 
flues  with  suitable  dampers  for  directing  the  fire 
gases. 


It  takes  more  fuel  where  the  retorts  are  protect- 
ed, also  where  cars  are  used.  More  damage  is 
caused  without  protection  also  with  cars  as  the 
shells  must  be  made  hotter  in  the  latter  case.  A 
small  retort  takes  more  labor  than  a  large  one, 
but  has  proportionately  more  heating  surface.  The 
use  of  steam  is  recommended  with  these  processes 
under  the  same  conditions  as  with  chipped  wood, 
only  for  a  longer  time. 

Steam  Processes.— Under  this  head  will  be  com- 
prised those  processes  using  steam  with  or  without 
pressure  for  extracting  the  turpentine.  In  this 
process  nothing  is  obtained  but  the  turpentine,  al- 
though some  utilization  of  the  residue  is  attempted. 
The  steam  process  has  several  distinct  advantages 
over  the  others.  Some  of  them  are  that  the  wood 
being  in  a  fine  state  of  division  the  process  does 
not  take  but  from  one  to  six  hours  against  24  to 
48  by  the  destructive  method.  The  turpentine  pro- 
duced is  of  a  more  uniform  quality,  the  apparatus 
is  not  destroyed  and  the  residue  left  after  distill- 
ing is  sufficient  for  the  fuel  necessary  to  furnish 
the  steam  and  cooling  water.  On  the  other  hand, 
it  has  the  distinct  disadvantage  in  localities  where 
charcoal  is  in  demand  of  not  being  able  to  utilize 
a  poor  ouality  of  wood  except  where  such  wood 
has  but  little  value,  such  as  sawdust.  Where  wood 
is  relatively  expensive  the  steam  process  will  not 
draw  out  enough  turpentine  to  pay  for  the  wood 
itself.  This  must  be  taken  into  consideration  in 
deciding  about  building  a  plant. 

la  reviewing  some  of  the  patents  on  the  subject 
one  finds  that  the  use  of  steam,  superheated  and 
saturated,  with  and  without  pressure,  has  been  pat- 
ented since  1865  by  Hall  and  Emery,  and  the  same 
was  probably  in  use  before  that  time.  Since  then 
numerous  patents  have  been  obtained  for  practical- 
ly the  same  principle,  but  with  the  retort  slightly 
modified  in  some  particular.  As  all  these  steam 
methods  were  followed  with  destructive  distilla- 
tion they  will  be  found  under  that  head.  Of  those 
processes  which  stopped  the  distillation  when  the 
turpentine  was  distilled,  the  one  that  first  attract- 
ed much  attention  was  Krug's  patent,  exploited  by 
the  Standard  Turpentine  Company,  wno  located 


52 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


their  first  plant  at  Waycross,  Ga.  An  ordinary 
hardwood  distillation  plant  was  erected  with  re- 
torts having  a  bumped  head  to  stand  the  pressure. 
Each  retort  was  mounted  with  a  steam  gauge  and 
two  valves,  one  valve  leading  to  a  condenser  for 
turpentine,  and  the  other  leading  to  a  condenser 
for  tar  products.  The  turpentine  valve  was  sim- 
ply a  relief  valve  opening  at  a  definite  pressure. 


FIG.   21.— KRUG'S   PATENT    (PLAN). 

The  object  of  the  process  seemed  to  be  to  steam 
off  the  oil  and  then  to  destructively  distill  the 
residue  if  required.  Upon  trial  the  troubles  of  the 
earlier  investigators  were  encountered,  one  great 
difficulty  arose  in  the  inability  of  steam  even  under 
pressure  to  remove  all  the  oil  from  a  block  of  wood 
in  the  time  of  distillation.  To  obviate  this  the 


wood  was  ground  up  in  a  hog  and  then  distilled. 
Under  these  conditions  much  success  was  claimed 
in  extracting  the  turpentine.  Of  course,  owing  to 
the  fine  conditions  of  the  wood,  destructive  distill- 
ation was  not  to  be  thought  of.  Another  trouble 
with  the  plant  was  the  difficulty  in  charging  and 
discharging  the  retort  with  the  fine  wood.  The  re- 
torts being  horizontally  placed,  it  was  necessary 
to  throw  the  material  in  by  hand.  At  another 
plant  constructed  by  the  main  company  the  re- 
torts were  set  vertically,  thus  enabling  them  to  be 
charged  by  means  of  a  conveyor.  This  process 
was  interesting  and  great  credit  is  due  to  the  pro- 
moters. The  idea  has  been  copied  in  many  forms, 
some  using  pressure  and  some  not,  the  most  im- 
provement being  made  in  the  mechanical  handling 
of  the  raw  material.  As  to  the  validity  of  any  of 
these  patents  there  must  be  some  doubt. 

Fig.  21  shows  the  retort  used  in  this  process 
and  the  mountings.  A  is  the  retort  with  bumped 
heads;  a  is  an  inlet  for  steam  which,  however, 
is  not  usually  used,  the  steam  being  taken  in  from 
the  top  at  the  front  end  and  a  perforated  coil 
placed  in  the  retort.  The  retort  being  set  in  a 
brick  furnace  external  heat  can  be  applied  with 
the  steam  if  necessary.  The  turpentine  valve  B3 
is  an  ordinary  valve  which  can  be  closed  when 
necessary,  while  at  B2  is  the  automatic  valve  to 
regulate  the  pressure.  At  D  the  tar  vapors  can 
arise  and  pass  through  D2  to  the  condenser  E  and 
discharge  at  C3.  The  valve  D2  probably  wouldn't 
work  but  once  without  choking  with  pitch  or  coke. 
The  turpentine  vapors  after  passing  B2  pass  to  the 
turpentine  condenser  C  where  they  would  be  con- 
densed and  discharged.  Two  retorts  are  connect- 
ed with  one  condenser,  as  shown.  The  illustra- 
tion represents  a  plan,  the  Upper  parts  of  the  ap- 
paratus being  shown. 

Another  patent  along  the  same  lines  as  the 
foregoing  is  that  of  Hoskins,  shown  in  Fig.  22. 
One  of  the  methods  suggested  of  utilizing  hogged 
pine  wood  and  saw  dust  has  been  to  make  it  into 
paper.  This  patent  endeavors  to  show  a  method 
by  means  of  which  the  turpentine  can  be  distilled 
and  the  hogged  wood  remaining  in  the  retort 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


53 


cr  digester  can  be  treated  with  caustic  soda  to 
form  wood  pulp.  In  the  illustration  A  represents 
the  digester  made  very  strong  in  order  to  with- 
stand heavy  pressure.  The  digester  is  surrounded 
with  a  steam  jacket  (a)  provided  with  an  inlet 
pipe  (al)  and  outlet  pipe  (a2),  a  steam  tight 
charging  door  (b)  near  its  upper  end  and  a  steam 
tight  discharging  or  clean-out  door  (c)  at  the  low- 
er end.  In  the  digester  chamber  is  an  outer  steam 
coil  (d),  having  a  valved  inlet  pipe  (dl)  and  outlet 


with  a  valved  cold-water-inlet  pipe  (k)  and  a  water- 
outlet  pipe   (kl). 

The  turpentine  is  steamed  off  and  condensed  in 
the  condenser  shown.  During  the  operation  the 
resin  collects  on  the  bottom  and  can  be  drawn  off 
at  f.  Care  is  taken  not  to  get  the  wood  too  hot 
and  spoil  the  pulp.  After  the  turpentine  has  been 
extracted,  caustic  soda  of  about  1.20  sp.  gr.  is  put 
into  the  digester  and  the  whole  heated  and  the 
pressure  raised  to  75  or  90  Ibs.  for  six  to  twelve 


FIG.    22.— HOSKINS    PATENT. 


pipe  (d2)  and  an  inner  perforated  steam  coil  (e) 
having  a  valved  inlet  pipe  (el).  Extending  through 
the  cover  (c)  at  the  lower  end  of  the  digester  is 
an  outlet  pipe  (f)  provided  with  a  valve  (fl)  and 
extending  from  the  top  of  the  digester  is  an  outlet 
pipe  (g)  provided  with  a  valve  (gl).  Interposed 
in  the  pipe  (g)  is  a  pressure  gauge  (h);  the  pipe 
(g)  leads  to  the  upper  end  of  the  coil  (i)  of  the 
condenser  (B).  In  the  outlet  pipe  (il)  of  the  coil 
(i)  is  a  valve  (i2)  and  the  condenser  is  provided 


hours,  according  to  the  quality  and  quantity  of 
the  wood  treated.  The  alkaline  liquor  is  drawn 
off  and  treated  as  in  paper  mills  or  destructively 
distilled.  The  wood  pulp  is  blown  out  and  is  ready 
for  further  treatment  in  the  paper  mill.  The  qual- 
ity of  paper  made  by  pine  will  be  spoken  of  later. 
In  this  process  one  operation  could  be  made 
to  do  the  work  of  two  if  the  turpentine  was  taken 
off  when  the  wood  was  being  treated  with  caustic 
soda  instead  of  before. 


54 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


The  next  steam  process  to  be  considered  is  that 
of  Mallonee,  different  in  one  important  respect 
from  Krug's,  in  that  it  provides  a  means  of  stirring 
the  chipped  wood.  The  process  is  evidently  sim- 
ply a  modification  of  Krug's.  From  the  illustration 
in  Fig.  23  the  essential  parts  are  readily  to  be 
seen.  The  retort  is  at  1  Fig  1,  and  is  fitted  with 
a  mechanical  stirrer  operated  by  means  of  gear 
wheels.  At  17  is  a  manhole  for  the  entrance  of 
the  chipped  wood  and  for  cleaning  out  purposes. 
Live  steam  is  introduced  through  the  perforated 
shaft  of  the  stirrer  and  for  heating  the  resin  a 
closed  coil  is  placed  on  the  bottom.  At  16  is  a 
pipe  and  valve  for  drawing  off  the  hot  resin  and 
at  14  a  pipe  for  leading  the  turpentine  to  the  con- 


ued  by  means  of  the  closed  coil  for  a  short  while 
until  the  resin  settles,  when  this  is  drawn  off.  The 
pulp  is  then  run  into  the  still  19  and  heated  under 
pressure  of  60  to  100  Ibs.  by  means  of  steam  or 
otherwise,  a  weak  solution  of  caustic  soda  being 
added  to  extract  the  resin.  The  relief  valve  opens 
with  an  excess  of  pressure,  allowing  the  turpen- 
tine to  escape  to  the  condenser.  After  the  oil  has 
ceased  flowing  the  pressure  is  gradually  removed 
and  the  contents  discharged. 

As  shown  in  the  illustration,  this  process  does 
not  present  many  merits.  The  stirrer  would  be 
very  inefficient  if  the  retort  w«re  nearly  full  of 
wood  and  at  one  plant  where  a  similar  stirrer  was 
used  they  were  found  to  be  liable  to  be  destroyed 


FIG.    23— MALLONEE'S    PROCESS. 


denser.  The  second  still  shown  in  Fig.  2  is  used 
to  extract  the  remaining  turpentine  and  resin  from 
the  wood.  This  latter  is  simply  a  retort  with 
bumped  head  furnished  with  relief  valve  and 
gauge  and  draw-off  pipe  similar  in  nearly  all  re- 
spects to  the  Krug  retort  before  described. 

To  use  the  apparatus  the  wood  mixed  with  wat- 
er is  charged  into  the  retort  or  still  through  the 
manhead  shown  in  Fig.  1;  at  the  same  time  the 
stirrer  is  put  in  motion.  When  sufficiently  full 
the  contents  are  heated  by  means  of  the  closed 
coil  until  the  water  begins  to  distill  (known  by  the 
pipe  14  becoming  warm),  then  live  steam  is  turned 
on  under  low  pressure,  and  the  turpentine  carried 
over  and  condensed.  When  the  oil  ceases  to  distill 
the  live  steam  is  shut  off  and  the  heating  contin- 


by  the  arms  being  broken  off.  Using  water  in 
charging  the  arms  can  work  more  freely,  but  un- 
less there  was  a  lot  of  water  in  the  retort  (in 
which  case  much  more  heat  would  be  required), 
channels  would  form  where  the  arms  turned  and 
the  stirring  would  not  be  very  effective.  Also,  the 
necessity  of  charging  and  discharging  two  retorts 
or  stills  in  the  manner  shown  would  prove  a 
great  drawback.  As  is  the  case  with  the  previous 
process,  the  necessity  of  the  first  part  of  the  oper- 
ation does  not  seem  apparent. 

Another  process  for  the  removal  of  the  turpen- 
tine vapors  from  ground  wood  is  that  of  Hirsch, 
shown  in  Fig.  24.  In  this  process  the  difficulty  of 
discharging  the  horizontal  retorts  in  the  Krug  and 
Mallonee  process  is  done  away  with.  Here  the 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


55 


retort  or  still  is  set  vertical,  the  wood  entering 
the  door  14,  fills  the  interior  and  is  ready  for  dis- 
tillation. Steam  is  turned  on  by  means  of  a  per- 
forated pipe  and  the  pressure  allowed  to  rise  to 
60  Ibs.,  which  is  indicated  by  the  relief  valve  28, 
and  gauge  29.  When  the  pressure  reaches  60  Ibs., 
the  large  valve  32,  is  opened  and  the  turpentine 
sent  to  the  condenser.  When  the  distillate  con- 
tains but  a  small  amount  of  turpentine,  the  steam 
is  shut  off  and  the  refuse  wood  drawn  out  through 
the  bottom  doors.  The  valve  32,  might  be  a  relief 
valve  the  same  as  in  the  Krug  and  Mallonee  proc- 


difficulty  is  removed  in  this  process.  Unless  some 
form  of  rotating  retort  is  discovered  which  will 
give  sufficiently  greater  yields  in  a  given  time  to 
pay  for  its  extra  initial  cost,  this  process,  or  the 
various  modifications  of  it,  will  prove  to  be  the 
best  for  all-round  work.  Mallonee  in  his  process 
claims  as  one  reason  for  stirring  the  material  that 
the  yield  is  greatly  increased  and  the  time  of  opera- 
tion lessened.  This  can  be  done  better  with  a 
stirrer  with  vertical  shaft  than  with  a  horizontal 
one,  but  none  are  entirely  satisfactory,  as  saw 
dust  is  not  easily  stirred. 


FIG.  24-^HIRSCH'S  PROCESS. 


esses.  The  advantages  and  disadvantages  of  the 
apparatus  are  apparent  from  the  illustration. 

There  are  a  great  many  companies  offering  ap- 
paratus for  sale  under  patents  all  described  simi- 
lar to  the  process  which  we  will  now  consider. 

In  the  Gardner  process  we  find  the  best  arrange- 
ment of  any  steam  process.  The  whole  success  of 
the  steam  processes  depends  upon  the  mechanical 
arrangements  for  handling  the  wood.  In  the  above 
processes,  it  has  been  noticed  that  the  cost  of 
operating  with  saw  dust  or  other  material  giving 
light  yields,  would  be  too  great  on  account  of  the 
disadvantageous  methods  of  handling  the  raw  ma- 
terial. We  will  see  from  the  illustration  how  this 


Gardner's  process  is  illustrated  in  Fig.  25.  In 
practice  only  one  retort  is  used,  the  upper  one 
being  found  unnecessary.  Often  a  simple  bin  is 
used  in  its  stead. 

To  operate  the  conveyor  6,  brings  the  hogged 
wood  and  saw  dust  and  deposits  it  into  the  bin, 
from  whence  it  falls  into  the  retort  2.  All  the 
openings  are  then  closed  and  fastened,  except  the 
vapor  pipe  11.  A  false  bottom  10,  serves  to  keep 
the  saw  dust  from  falling  into  the  vapor  pipe. 
Steam  is  turned  in  by  means  of  pipes  14  and  15, 
the  distilled  turpentine  passing  out  at  the  bottom. 
The  stirrers  12,  are  turned  to  keep  the  saw  dust 
from  packing.  After  the  oil  is  extracted  the  hot- 


56 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


torn  is  dropped,  as  shown,  and  the  material  falls 
out  in  bulk.  The  residue  dries  quickly  and  can 
be  used  for  fuel. 

The  next  steam  process  to  be  considered  is  that 
of  W.  W.  and  T.  L.  James.  The  illustration,  Fig. 
26,  shows  a  rectangular  box  retort  standing  on 
edge,  supplied  with  steam  coils  and  also  perforat- 
ed pipes  for  live  steam.  The  turpentine  is  ex- 


FIG.    25— GARDNER'S    PROCESS. 

tracted   by   means   of   steam   under   pressure,    the 
pressure  being  controlled  by  relief  valve  32. 

This  form  has  a  bad  shape  for  pressure,  and  at- 
tempts are  made  to  keep  the  sides  from  bulging  by 
means  of  bolts.  It  has  nearly  every  conceivable 
disadvantage  as  compared  with  other  steam  proc- 
esses, and  but  one  slight  advantage  in  that  it  takes 
less  cooling  water,  the  condensing  being  done  by 


mixing  the  combined  vapors  with  water  by  uniting 
water  pipe  13,  with  vapor  pipe  33.  Even  then, 
an  ordinary  jet  condenser  would  be  a  better  ar- 
rangement. 

The  McMillan  process  was  devised  to  supply  a 
means  of  rapidly  discharging  the  retort  after  the 
ground  wood  has  been  distilled.  The  arrangement 
consists  of  an  iron  retort  set  vertically  with  an 
inner  device  J,  Fig.  27,  composed  of  several  sec- 
tions, each  one  of  which  is  separate  from  the  others 
and  capable  of  being  forced  together  or  opened 
by  means  of  the  bolts  L. 

The  wood  enters  through  the  large  valve  D,  and 


FIG.   26— JAMES'    PROCESS. 

drops  into  the  device  J,  where  it  is  distilled  by 
means  of  steam  entering  at  A,  the  vapors  passing 
out  at  E.  At  F  is  a  safety  valve  and  at  R  is  a  dis- 
charge pipe  for  rosin,  tar,  etc.  After  the  turpen- 
tine has  been  extracted,  the  valves  are  all  closed 
and  the  sections  of  the  inner  device  J,  loosened 
by  means  of  the  bolts  L,  thus  allowing  the  distilled 
residue  to  fall  to  the  bottom  ot  the  retort.  The 
discharged  gate  B  is  then  opened  and  steam  or  air 
added  through  A — Al,  and  the  residue  blown  out. 
It  can  be  readily  seen  that  as  wood  swells  when 
steamed  and  is  difficult  to  remove  from  the  retort 
on  that  account,  such  a  device  would  overcome  this 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


57 


FIG.    27— MCMILLAN'S    PROCESS. 


difficulty  nicely.  However,  stirrers  should  be  used 
in  order  to  obtain  the  best  results,  and  with  these 
the  material  ought  to  be  so  loosened  as  to  easily 
fall  out  of  an  ordinary  retort  such  as  Gardner's. 
On  this  account,  such  a  device  is  too  expensive 
for  the  result's  obtained. 


STEAM      AND      DESTRUCTIVE      DISTILLATION 

AND    DESTRUCTIVE    DISTILLATION 

PLANTS. 

There  are  two  methods  of  destructively  distilling 
wood,  one  using  steam  to  take  off  the  turpentine 
and  the  other  not  using  any.  Plants  designed  for 
the  latter  method  can  be  easily  changed  to  the 
first  form  by  simply  adding  a  steam  pipe,  so  in 
considering  these  plants  they  will  be  classed  to- 
gether. The  use  of  steam  is  considered  by  some 
to  be  injurious  to  the  oil  produced  and  also  to  in- 
crease the  time  of  distilling.  However,  most 
plants  get  better  oil  and  better  results  with  the  use 
of  steam. 

The  use  of  steam  followed  by  destructive  distil- 
lation, would  form  an  ideal  process  if  it  were  not 
for  the  great  drawback  that  steam  will  not  take 
out  all  the  turpentine  from  a  block  or  wood  with- 
out decomposing  the  woody  fiber,  except  by  pro- 
longed heating.  That  it  will  do  so  if  heated  long 
enough,  has  been  satisfactorily  proven,  particularly 
in  the  case  of  short  pieces,  such  as  sawed  knots. 
If  the  wood  were  hogged  then  steam  would  take 
out  the  oil  readily,  as  is  observed  in  the  steam 
process,  but  this  spoils  it  for  charcoal,  without 
which  product  the  destructive  process  cannot  hope 
to  pay.  Furthermore,  saw  dust  has  been  found 
very  difficult  to  distill  destructively  until  recently. 
The  fine  wood  chars  near  the  shell  of  the  retort, 
but  the  heat  cannot  penetrate  to  the  middle  very 
easily,  even  in  retorts  of  small  diameter.  Special 
retorts  to  be  described  later  overcome  the  diffi- 
culty of  distilling,'  but  the  fine  charcoal  must  be 
disposed  of  at  a  good  price  in  order  to  make  the 
process  pay.  Briquetting  may  help  if  the  right 
kind  of  bond  can  be  found. 

Unless  such  a  process  as  above  described  can 
be  discovered,  those  plant's  now  to  be  considered 
must  be  located  near  a  supply  of  rich  wood  and 
have  a  ready  market  for  their  charcoal.  Bad  loca- 
tion has  been  the  cause  of  many  a  failure.  When 
well  located,  though,  these  processes  are  much 
more  valuable  than  the  steam  process  alone,  be- 
cause all  the  valuable  products  are  obtained  from 


58 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


wood  and  only  cheap  refuse  is  used  for  fuel.  A 
process  that  can  utilize  the  wood  without  having 
to  use  part  of  the  prepared  material  to  fire  the 
furnaces  of  the  plant  itself,  is  the  process  that 
would  be  the  most  acceptable.  Whether  such  a 
process  will  ever  be  discovered  it  is  difficult  to 
determine.  In  the  steam  process  the  utilization  of 
the  pulp  for  the  manufacture  of  alcohol,  oxalic 
acid  or  possibly  cellulose  might  prove  a  satisfac- 
tory solution  of  the  problem. 

As  before  stated,  wood  distilling  plants  operating 
on  pine  wood  were  in  use  before  1865.  The  patent 
records  mention  the  devices  of  Hull  and  Emery 


present  position  from  the  middle  of  the  top  of  the 
retort.  The  retort  is  shown  at  A,  supplied  with 
steam  through  valve  e.  The  turpentine  vapors 
pass  through  pipe  I,  through  tank  O,  containing 
hot  milk  of  lime,  and  cooled  in  the  condenser  Y. 
The  creosote  vapors  go  through  K  and  condense  in 
R;  any  heavy  tar  condensed  in  pipe  K,  flowing 
down  pipe  V.  When  I  and  K  are  closed,  the  un- 
condensed  gas  and  heavy  vapors  formed  coming 
from  pipe  H,  can  pass  up  this  pipe  to  the  worm  r, 
where  the  vapors  will  be  condensed  while  the  gas 
passes  through  S,  to  separator  T,  to  gas  main  P. 
For  about  three  or  four  hours  the  retort  is  heat- 


FIG.    28— WHEELER'S    PROCESS. 


about  that  time.  They  distilled  without  steam, 
and  with  steam  at  ordinary  pressure  and  heavy 
pressure. 

A  division  of  the  later  processes  will  be  made 
into  those  using  horizontal  retorts  and  those  using 
vertical  retorts. 

Horizontal    Retorts. 

Wheeler's  Process. — A  process  for  the  extraction 
of  oils  from  pine  wood  was  patented  in  1870  by 
Wheeler,  and  improvements  added,  as  shown  in 
Fig.  28. 

In  this  process,  the  valves  i,  k  and  h,  were  added 
to  his  original  idea  and  the  pipe  I,  changed  to  its 


ed  at  a  very  low  temperature  by  means  of  a  low 
fire  and  live  steam  and  the  turpentine  taken  off 
through  pipe  I.  The  valve  i,  and  the  steam  valve 
are  then  closed  and  the  retort  heated  to  230  degrees 
Fahrenheit,  for  about  two  hours,  the  vapors  now 
passing  through  valve  k,  and  the  gas  separating 
from  the  condensed  liquors  at  T,  going  to  the 
holder  P.  The  receiver  being  changed,  the  vapors 
formed  at  300  degrees  to  400  degrees  Fah.,  pass 
through  the  same  exit  K,  and  this  heating  contin- 
ues for  six  hours.  The  valve  h,  being  opened 
and  the  valve  k,  closed,  the  tar  and  gas  flow  out 
through  pipe  H,  for  about  an  hour  or  so.  As  the 
retort  holds  but  a  cord,  this  severe  heating  does 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


59 


not  affect  it  so  much  as  it  would  if  it  were  larger. 
This  separation  of  the  vapors  will  be  noticed  in 
later  patents. 

Several  other  patents  followed  Emery's  before 
Wheeler's,  but  they  are  not  of  sufficient  importance 
to  describe.  Mention  has  been  made  of  Stanley's 
patent.  This  process  was  patented  later  than 
Wheeler's  and  comprised  an  ordinary  distilling  ap- 
paratus consisting  of  retort  and  condenser,  with 
necessary  arrangements  for  heating.  This  ap- 
paratus was  sold  to  the  Spiritine  Chemical  Com- 
pany, who  found  it  convenient  to  improve  accord- 


others;  the  turpentine  being  taken  off  at  a  low  tem- 
perature, the  tar  oil  next  and  the  tar  running  out 
the  back  pipe.  A  modification  of  this  process  con- 
sists in  substituting  a  bee-hive  brick  retort  in  place 
of  an  iron  one. 

The  next  process  is  that  of  Hansen  &  Smith. 
The  retort  is  known  in  the  hardwood  industry  as  a 
double  ender,  on  account  of  there  being  a  fireplace 
at  each  end.  The  retort  B,  Fig.  30,  is  made  about 
25  or  26  feet  long  and  holds  about  six  cords  of 
wood.  The  wood  is  run  in  on  cars,  as  at  F,  Fig.  1. 

To  distill  the  wood  a  fire  is  started  at  both  ends 


FIG.   29— MESSAU'S   PROCESS. 


ing  to  Hansen's  patent,  which  will  be  described 
later. 

Messau  process,  illustrated  in  Fig.  29,  is  of  in- 
terest, as  two  features  are  brought  in  that  may 
affect  later  conditions;  first  a  method  of  super- 
heating is  shown,  then  a  method  of  adding  air  to 
the  charge. 

In  the  illustration,  A  is  the  retort  and  S  the  su- 
perheater. The  retort  is  of  boiler  iron  and  inclined 
so  that  the  liquid  products  can  escape  at  the  bot- 
tom pipe  on  the  right.  The  fire  does  not  touch  the 
bottom;  the  heat  passing  by  means  of  suitable  flues 
so  as  to  heat  the  contents.  To  assist  the  heating, 
air  is  admitted  at  G.  The  operation  is  similar  to 


of  the  retort,  the  flame  passing  to  the  partition  A, 
through  the  opening  g,  then  winding  around  the  re- 
tort, being  guided  by  the  partitions  bl  and  b2,  and 
finally  escaping  by  means  of  the  stack  b3,  to  the 
air.  The  bottom  of  the  retort  is  protected  from 
the  direct  flame  by  means  of  the  arch  al.  The 
vapors  pass  out  through  pipe  f,  to  a  suitable  con- 
denser. After  the  wood  is  charred  the  fires  are 
put  out  and  the  furnace  cooled  by  means  of  a  ven- 
tilating fan,  shown  at  H,  connected  with  h  of  the 
furnace,  Fig.  1.  This  apparatus  was  intended  to 
produce  wood  creosote,  which  was  then  used  for 
creosoting  lumber. 

There   are   several   Koch   processes   that  are   in 


60 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


use,  plants  being  built  similar  to  each  one.  These 
plants  have  nearly  all  proveu  failures  for  some  rea- 
son or  other.  The  principal  reason  seems  to  be 
small  yields  from  the  wood  used  and  a  poor  mar- 
ket. 

They  have  two  bad  features,  one  is  a  brick  arch 
for  protecting  the  retort  and  the  other  is  the  use 
of  a  closed  car.  Both  of  these  features  mean  «u. 
increased  cost  for  fuel.  Too  much  of  the  heat  g\*«s 
up  the  chimney  during  the  latter  part  of  the 
operation.  The  arch  does  protect  the  retort  and  is 


Fig.  31.  The  retort  A,  can  be  made  of  any  size 
and  rails  laid  hear  the  bottom.  The  car  K,  is 
filled  with  wood  and  rolled  into  the  retort,  the  door 
of  which  is  then  closed.  A  fire  is  started  in  the 
furnace  at  D  and  the  flame  follows  the  flue  d.  until 
it  reaches  the  baffle  at  the  end  of  the  retort  then 
returns  by  means  of  arched  brick  flues  E,  El,  Fig. 
8,  to  the  front  of  the  furnace,  then  instead  of  unit- 
ing under  the  retort  and  burning  a  hole  therein, 
the  flames  enter  the  side  walls  at  g  and  then  rush 
back  along  the  sides  of  the  retort  to  the  back  flue 


FIG.  30— HANSEN  &  SMITH  PROCESS. 


of  value  where  large  retorts  are  used  and  fuel  iS 
cheap.  The  car  is  a  rapid  way  of  withdrawing  the 
charcoal,  but  those  plants  using  these  cars  find 
that  the  wood  is  not  evenly  heated,  the  wood  in 
one  part  being  charred  before  the  turpentine  is 
extracted  from  the  wood  in  another  part.  It  may 
be  that  the  furnace  flues  could  be  proportioned 
better  and  the  cars  be  made  of  openwork  structure, 
so  that  they  can  be  more  readily  heated.  In  this 
case,  a  cooler  should  be  used  into  which  the  char- 
coal could  be  drawn. 

Parts  of  some  of  these  processes  are  shown  in 


h  and  then  down  to  i,  which  communicates  with 
the  stack.  This  furnace  seems  to  answer  the  pur- 
pose very  well  when  properly  constructed,  but  with 
oil  fuel,  the  back  wall  at  E  has  a  bad  habit  of 
dropping  when  the  furnace  gets  hot.  This  trouble 
is  not  experienced  with  wood. 

As  the  heating  continues,  superheated  steam  is 
let  in  from  pipe  b,  until  the  turpentine  is  distilled, 
when  the  steam  is  shut  off  and  the  distilling  fin- 
ished by  the  heat  of  the  fire.  The  vapors  leave 
the  retort  at  r  and  follow  the  pipe  to  w.  This  valve 
is  closed  when  making  turpentine  and  the  valve  V 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


61 


open  and  the  oily  vapors  thus  escape  through  pipe 
P,  to  a  condenser.  After  the  turpentine  is  taken 
off,  the  valve  w,  is  opened  and  valve  V,  closed, 
the  heavy  vapors  going  to  p,  where  part  of  them 
are  condensed  and  the  remainder  and  uncondensable 
gases  pass  through  u  to  a  condenser  and  gas  sep- 
arator. To  prevent  a  deposit  of  tarry  matter  in 
the  pipe  r,  it  is  surrounded  by  water  contained  in 
the  trough  W. 

Instead  of  using  the   pipe  as  herein  shown,  the 


much  trouble.  As  before  stated,  it  takes  consider- 
able fuel  as  now  carried  on.  The  use  of  cars  was 
practiced  in  the  hardwood  industry  before  this 
process  was  patented,  and  their  use  will  be  noticed 
in  Hansen's  &  Smith's  process,  previously  de- 
scribed. The  subject  will  be  brought  up  again 
later. 

It  has  been  stated  that  in  the  hardwood  indus- 
try small  retorts  are  used  very  successfully  for 
carbonizing  wood.  By  connecting  these  retorts 
with  suitable  condensers,  they  can  be  used  for  dis- 
tilling pine.  One  of  the  most  successful  de- 


FIG.    31— KOCH'S   PROCESS. 

pipe  in  practice  is  lowered  to  Z,  the  cross  R  being 
left  out.  The  water  jacket  is  then  brought  into 
connection  with  the  back  end  of  the  retort.  By 
this  arrangement  the  pipe  r,  is  found  to  remain 
free  from  a  heavy  deposit  of  carbon.  Often  a  tar 
pipe  is  placed  at  the  bottom  of  the  front  end  of 
the  retort,  by  means  of  which  the  hot  tar  can  be 
removed  without  vaporizing  it. 

Under  proper  conditions,  with  well  proportioned 
furnaces,  this  process  ought  to  distil  wood  without 


FIG.  32— BADGLEY'S  PROCESS. 


structive  distillation   plants   in   the    South  is   com- 
prised of  a  series  of  such  retort's. 

To  protect  the  brickwork,  when  two  of  such  re- 
torts are  set  in  one  furnace,  Badgley  devised  the 
apparatus  shown  in  Fig.  32.  It  consists  of  a  i 
shaped  bar  placed  between  the  retorts  and  held 
in  position  by  bolts  m,  n,  etc.,  passing  through 
the  furnace  to  the  rear  wall.  Rollers  are  placed 
at  q,  q,  upon  which  the  retort  can  be  turned  if 
necessary.  Arrangements  are  also  made  so  that 
the  swollen  retort  can  be  easily  withdrawn  when 
burned  through*.  The  other  features  of  the  proc- 


62 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


ess  are  not  of  particular  interest  to  the  pine  wood 
distiller. 

Another  arrangement  for  turning  the  retorts  is 
shown  in  Inderlied's  patent,  Fig.  33.  The  rollers 
at  a  and  the  balls  at  b  b  facilitate  the  turning  of 
the  retort.  An  arrangement  is  also  made  to  con- 


FIG.   33— INDERLIED'S   PROCESS. 

trol  the  fire  gases  so  that  they  will  not  accu- 
mulate at  one  place  on  the  retort.  No  brick  pro- 
tection is  shown,  the  fire  gases  arising  envelop- 
ing the  retort  and  pass  out  through  the  ports  e  e  e, 
etc.,  into  the  flue  f  and  thence  to  the  chimney. 
Each  of  these  port  holes  can  be  closed  by  means 
of  a  damper  if  necessary. 

The   flange   on   the   vapor   pipe   is   arranged   so 
that  the   retort   can   be   given   a   sixth   of   a  turn 


or  more  at  a  time.  Instead  of  putting  two  retorts 
in  a  furnace,  as  in  Badgley's,  this  method  only 
allows  but  one.  However,  although  the  furnace 
construction  costs  more  with  only  one  retort  in  a 
setting,  it  is  so  much  more  easy  to  control  the 
operation  when  one  is  used  that  perhaps  tbis  ar- 
rangement might  be  best  with  pine  wood. 

If  large  retorts  are  to  be  used  in  pine  wood 
distillation,  the  oven  form  having  given  satisfac- 
tion in  the  hardwood  industry  ought  to  be  satis- 
factory when  distilling  pine.  Usually  these  are 
heated  by  natural  gas  or  oil,  but  Chapman  has 
designed  a  furnace  shown  in  Fig.  34  that  is  in- 
tended for  saw  dust  and  wood  firing.  Whether 
such  are  in  use  or  not  the  author  does  not  know. 

The  oven  is  at  A  set  in  a  double-ended  fur- 
nace. The  bottom  is  protected  by  means  of  the 
tile  arch  E,  in  which  are  port  holes  to  allow  some 
of  the  fire  gases  to  pass  through,  the  remainder 
turning  back  under  the  overhanging  arch  F  and 
thus  enter  the  space  beneath  the  retort.  In  this 
manner  th«  heat  is  to  be  uniformly  distributed. 
It  is  more  than  likely  that  in  practice  the  flames 
coming  through  e,  striking  the  bottom  of  the  oven, 
will  burn  a  hole  therein. 

The   firebox   is   so   constructed   that   air   can   be 


FIG.    34— CHAPMAN'S    PROCESS. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


63 


supplied  through  c,  so  as  to  burn  the  saw  dust 
fuel  from  the  top  and  also  to  act  as  a  feed  hole. 

These  retorts  can  be  made  50  feet  long  and 
should  be  supplied  with  rails  upon  tbe  bottom  on 
which  cars  carrying  the  wood  can  be  rolled.  For 
pine  wood  distillation,  suitable  steam  pipes  could 
be  added  and  the  charge  distilled  in  the  usual 
way.  The  vapors  would  pass  out  through  vapor 
pipe  Al  to  a  suitable  condenser.  Arrangements 
should  be  made  so  that  the  charcoal  can  be  drawn 
out  hot. 

The  next  process  is  the  device  of  one  who  bas 
had  experience  in  both  hardwood  and  pine  wood 
distillation.  A  plant  is  now  in  operation  com- 


The  retort  is  at  A  and  inclined  so  that  the 
products  of  distillation  may  pass  out  at  B  at  the 
bottom.  This  pipe  B  is  set  in  brickwork  and 
thus  protected  from  the  direct  contact  of  the 
flame,  but  at  the  same  time  is  kept  warm  enough- 
so  that  the  tar  can  flow.  The  furnace  construc- 
tion differs  from  the  Koch  process  in  that  the 
flame  on  its  return  from  the  back  at  El  is  turned 
up  at  E2  instead  of  into  the  wall,  as  shown 
in  Fig.  31g.  The  object  sought  is  to  heat 
the  top  of  the  retort  more  than  the  bottom 
so  that  the  distillation  might  begin  at  the  top 
and  the  products  of  distillation  pass  out  at  the 
bottom.  The  idea  of  taking  off  the  products  of 


FIG.    35— GILMER'S   PROCESS. 


prising  twenty  of  such  retorts  in  batteries  of  five 
with  a  boiler  in  between.  Ten  retorts  are  in  line 
on  one  side  and  ten  on  the  other  with  the  charg- 
ing ends  on  the  outside  of  the  square  formed. 
The  vapor  pipes  are  thus  between  the  two  series 
of  retorts.  One  condenser  is  used  for  a  series  of 
retorts  for  the  various  grades  of  oil  distilled,  the 
vapors  from  each  retort  being  controlled  by  a 
series  of  valves. 

We  have  in  Fig.  35  the  illustration  of  the  set- 
ting of  one  of  these  retorts.  This  apparatus  was 
devised  after  several  years'  use  of  the  Koch  proc- 
esses, so  a  resemblance  to  them  in  many  respects 
may  be  expected. 


distillation  at  the  bottom  is  a  good  one  and  is 
practiced  largely  with  vertical  retorts,  particu- 
larly on  the  Pacific  coast.  One  would  think, 
though-,  that  the  vapors  of  turpentine  being  so 
light,  they  would  be  better  taken  off  at  the  top. 
Such  might  be  the  case,  but  the  proportion  of  other 
products  is  so  much  greater  and  the  vapors  so 
much  heavier  that  it  would  be  easier  to  take 
them  all  off  at  the  bottom.  Furthermore,  it  would 
be  necessary  to  vaporize  the  tar  to  drive  it  through 
a  high  pipe,  whereas  with  a  pipe  at  the  bottom  it 
can  be  drawn  off  as  a  liquid,  thus  saving  fuel. 
When  the  object  is  to  separate  the  vapors  into 
fractions  as  shown,  it  is  not  advisable  to  heat 


64 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


any  portion  of  the  retort  too  strongly,  as  other- 
wise the  wood  in  one  part  of  the  retort  would  be 
yielding  tar  before  the  wood  in  another  part  had 
lost  all  of  its  turpentine  and  thus  the  turpentine 
be  contaminated  with  tarry  vapors.  Other  dis- 
advantages of  heating  a  retort  at  the  top  would 
be  that  it  is  more  difficult  to  heat  the  top  than 
the  bottom;  a  fact  well  known;  and  also  that  in 
the  later  stages,  when  the  most  heat  is  required, 
the  wood  as  it  decomposes  settles  to  the  bottom, 
thus  getting  further  and  further  away  from  the 


pipe  from  the  other  retorts  of  the  same  series. 
In  a  similar  manner  when  the  proper  tempera- 
ture is  reached,  valve  i  is  opened  and  valve  h 
is  closed,  and  the  vapors  pass  through  I  to  an- 
other main  pipe.  Toward  the  latter  end  of  the 
distillation,  the  tar  flows  through  valve  g.  In  all 
cases,  the  uncondensable  gas  is  separated  at  the 
end  of  the  condenser.  „' 

The  collected  crude  products  are  sent  to  a  re- 
fining house,  where  they  are  specially  treated '"afc-^ 
cording  to  the  kind  of  product.  For  this  purpose 

\ 


FIG.  36— BROUGHTON'S  PROCESS. 


direct  heat,  and  at  the  last  stage,  when  the  most 
heat  is  required,  the  wood  is  nearly  half  the 
diameter  of  the  retort,  away  from  the  top.  It 
would  seem  that  a  definite  uniform  heat,  pro- 
gressing slowly  greater  in  intensity  until  the 
wood  is  charred,  is  better  than  to  heat  either  the 
top  or  the  bottom  to  a  different  degree;  then  by 
taking  off  the  products  of  distillation  at  the  bot- 
tom the  best  conditions  would  be  fulfilled  with 
little  decomposition  of  the  resin  or  vapors. 

As  the  products  come  over,  the  light  oils  pass 
up   the   vapor   pipe   H   and   connect    with    a    main 


copper  stills  are  used,  having  about  the  same 
height  and  diameter  and  furnished  with  suitable 
steam  coils,  vapor  connections,  etc.,  for  distilla- 
tion. The  turpentine  is  generally  once  distilled, 
then  treated  with  lime  and  aerated,  then  redis- 
tilled very  slowly  so  as  not  to  carry  over  any 
coloring  matter.  The  vapor  pipes  are  small  and 
carried  to  a  considerable  height  to  a  condenser, 
under  which  is  set  a  galvanized  tank  to  receive 
the  distillate.  The  water  is  drawn  off  from  time 
to  time,  leaving  the  oil,  which  is  placed  in  barrels 
for  shipping. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


65 


In  Broughton's  process,  Fig.  36,  steam  is  used, 
followed  by  destructive  distillation.  Here  an  at- 
tempt is  made  to  fractionate  the  oils  direct  from 
the  retort.  In  many  respects  it  resembles  Bil- 
finger's  process,  except  th-at  a  horizontal  retort  is 
used  instead  of  a  vertical  one.  In  the  illustra- 
tion the  process  looks  rather  complicated,  but  in 
reality  it  is  very  similar  to  others  and  can  be  op- 
erated as  readily.  The  refining  apparatus  is  also 
shown. 

The  retort  A  is  set  at  an  incline  to  the  front. 


liquor  to  the  heating  tank  Q,  from  whence  it  goes 
to  the  still  S  through  the  worm  V  to  receiver  W. 
To  operate,  the  wood  is  charged  at  a,  the  door 
fastened  and  steam  turned  on  at  about  300  de- 
grees Fah.  to  carry  off  the  major  portion  of  tur- 
pentine. This  continues  about  six  hours,  when  a 
fire  is  started  and  the  retort  heated  to  a  tempera- 
ture of  450  to  500  degrees  Fah.,  this  part  of  the 
operation  also  taking  about  six  hours.  The  steam 
is  then  shut  off  and  the  retort  gradually  heated 
to  about  800  degrees  Fah.,  or  until  the  wood  is 


FIG.    37— MALLONEE'S    PROCESS— Fig.    1. 


At  a  is  the  charging  door.  The  grates  are  in  the 
rear  of  the  furnace,  B,  one  each  side  at  bl  Fig.  2. 
By  the  arrangement  of  the  furnace,  the  direct 
flame  from  the  fire  cannot  affect  the  retort.  But 
it  is  a  very  poor  device  for  heating,  the  arrange- 
ment shown  in  Koch's  process,  Fig.  31,  being  far 
better.  The  vapor  pipe  for  the  light  oils,  E,  con- 
nects with  F,  a  contrivance  similar  to  the  barrel 
shown  in  Fig.  41  at  25  and  serves  the  same  pur- 
pose, that  of  separating,  partially,  light  oils  from 
heavy  oils.  J  is  the  condensing  tank,  K  the  gas 
pipe,  L  the  receiver.  O  is  a  pump  for  pumping  the 


thoroughly  carbonized.  The  turpentine  which 
comes  over  during  the  first  six  hours  goes  through 
E.  F.  H  and  J,  to  the  receiver  L,  the  heavier  oils 
going  down  Fl  to  G,  where  they  are  drawn  off. 
The  turpentine  and  some  creosote  that  comes  off 
during  the  next  six  hours  follow  the  same  course, 
the  tar  oils  and  some  creosote  dropping  down 
Fl  to  G  and  the  turpentine  and  some  creosote 
going  to  L.  The  tar  formed  flows  out  of  the  bot- 
tom pipe  c  into  the  trough  C.  This  comprises  the 
regular  operation  for  obtaining  the  crude  mate- 
rials. Only  the  turpentine  is  refined.  The  oil  is 


66 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


separated  from  the  water  in  the  receiver  L  and 
then  forced  by  the  pump  O  to  the  heater  Q,  which 
acts  as  a  sort  of  reservoir  for  the  still  S.  The 
oil  in  Q  is  heated  by  a  steam  coil  to  about  the 
boiling  point  of  turpentine  and  when  sufficient 
collects  in  the  heater  it  is  drawn  through  Rl  into 
the  still  S,  which  is  heated  by  a  closed  coil,  T,  at 
the  bottom.  The  shape  of  the  still  as  shown  is 
not  of  an  approved  pattern.  As  the  temperature 
is  raised  the  turpentine  distills,  aided  by  a  jet  of 
steam,  through  U  to  the  condenser  VI  to  the 
receiver  W,  where  it  is  ready  for  shipment. 


Mallonee's  process  sometimes  uses  steam  to  ex- 
tract the  turpentine  and  sometimes  not,  according 
to  the  operator.  There  are  several  processes  sug- 
gested by  the  same  inventor,  the  steam  process 
being  already  described.  The  illustration  Fig.  37 
shows  part  of  two  arrangements.  Fig.  1  shows  a 
double-ended  retort  set  in  a  special  furnace  so  ar- 
ranged that  the  bottom  of  the  retort  is  not  heated 
to  a  high  degree. 

Starting  at  12,  Fig.  2,  the  flame  goes  back  un- 
der the  arch  12-1  to  the  connecting  flue  17  by 
means  of  which  it  passes  to  16.  Following  16  to 


FIG.   37— MALLONEE'S   PROCESS— Fig.    2. 


This  process  offers  nothing  specially  new,  but  it 
brings  back  the  idea  of  refining  in  a  current  of 
steam  something  which  is  being  neglected  at 
plants  of  this  kind.  If  by  this  method  of  pro- 
cedure all  the  turpentine  in  the  wood  can  be  re- 
covered without  color  or  odor,  a  great  advance 
has  been  made  over  the  older  processes.  It  is 
doubtful,  though,  if  turpentine  containing  creosote 
can  be  refined  in  the  manner  described  and  creo- 
sote not  be  found  in  the  distillate. 


Fig.  1  it  passes  upwards  through  19,  then  rear- 
wardly  through  18,  then  upwards  through  20  into 
chamber  21.  Here  it  passes  along  the  sides  of  the 
retort  and  going  through  24  enters  the  chamber 
8  above  the  retort,  from  which  it  passes  through 
8-1  into  the  stack  39.  The  vapors  and  the  tar  fall 
to  the  bottom  and  flow  out  the  pipe  45,  while  the 
gases  pass  out  at  50. 

A   previous   patent   is    shown  in  Fig.  3  of  the  same 
illustration.     The   patent  claims   state   "tbat   here- 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


67 


tofore  the  method  commonly  used  consisted  in  re- 
ducing the  wood  by  means  of  fire  acting  on  the 
closed  retort  containing  the  wood  and  then  catch- 
ing and  condensing  all  the  distillate  in  one  bulk 
and  running  it  into  one  receptacle.  The  contents 
of  the  receptacle  were  then  refined  by  the  use  of 
an  ordinary  still."  As  the  Bilfinger  process  using 
vertical  retorts  was  being  exploited  before  this 
patent  was  applied  for,  it  is  surprising  that  it  was 
not  known  that  the  distillates  were  divided  into 
several  parts  by  other  parties.  Koch  and  Wheeler 
did  the  same  thing  sixteen  years  before. 

However,  the  method  as  used  in  this  process  is 
worth  considering,  for  a  distinct  method  is  de- 
scribed which  is  more  definite  than  some  others; 


3 


and  steam  turned  into  the  retort  to  help  carry 
the  vapors  to  the  condenser.  The  distillate  in- 
creases in  gravity  as  the  heating  progresses  and 
the  condensed  matter  is  allowed  to  flow  through 
the  cocks,  down  pipe  5d  (Fig.  3),  to  a  receiver 
until  the  sp.  gr.  reaches  0.92.  This  cock  is 
turned  off  and  the  distillate  allowed  to  flow 
through  cock  5-2  down  5c  until  the  sp.  gr.  reaches- 
0.96,  then  the  cock  5-3  is  opened  and  the  remainder 
of  the  distillate  allowed  to  flow  through  5-3  down 
pipe  5b  until  the  wood  is  thoroughly  charred. 


FIG.  37— MALLONEE'S  PROCESS— Fig.  3. 


FIG.  37— MALLONEE'S  PROCESS— Fig.  4. 


the  refining  operations  being  much  more  distinc- 
tive. 

In  the  illustration  1  represents  the  retort  set  in 
the  furnace  2,  steam  when  used  enters  at  3a.  The 
vapors  pass  through  la  to  the  condenser  5  and 
thence  through  the  gas  trap  to  the  liquor  separator 
5a.  The  refining  apparatus  is  shown  in  Fig.  4  of 
the  same  illustration.  The  still  6  is  of  ordinary 
construction  furnished  with  steam  closed  coils  7 
and  steam  jet  9.  The  light  oils  pass  through  valve 
19  up  pipe  13  about  twenty  to  twenty-five  feet, 
then  turn  to  the  condenser.  The  turpentine  which 
distills  later  is  allowed  to  pass  through  valve  20, 
the  condenser  valve  19  being  closed. 

To  operate,  the  wood  being  in  the  retort  and 
the  head  tightened,  fire  is  started  in  the  furnace 


The  second  part  of  the  operation  is  briefly  de- 
scribed. The  first  two  fractions  are  treated  sep- 
arately in  stills  of  the  construction  shown.  The 
idea  is  to  fractionate  the  oils.  To  do  this  the  first 
portion  of  the  distillate  is  allowed  to  go  up  pipe 
13  (Fig.  4),  where  the  pipe  is  cooled  by  water 
spray  near  the  top  at  21,  the  excess  water  being 
caught  in  pan  at  23.  This  has  a  tendency 
to  condense  the  heavy  oils  and  allow  only 
the  light  naphtha-like  oils  to  pass  over.  After 
these  are  taken  off  caustic  soda  of  about  1.20, 
amounting  to  5  or  10  per  cent  of  the  charge,  is 
allowed  to  gradually  enter  the  still.  This  causes 
frothing  and  when  it  subsides  more  naphtha-like 
oil  is  distilled  over,  then  as  the  turpentine  starts 
to  distill  it  is  turned  directly  into  the  condenser 


68 


THE    UTILIZATION    OF    WOOD    WASTB    BY    DISTILLATION. 


through  pipe  18,  the  valve  19  being  closed.  More 
details  will  be  given  under  refining  methods. 

The  third  fraction  is  treated  similarly  to  the 
otters,  except  that  caustic  soda  is  not  added.  When 
the  light  oils  from  this  third  fraction  cease 
coming  from  pipe  19,  part  of  the  residue 
in  the  still  will  pass  through  pipe  18  to 
the  condenser  when  valve  19  is  closed.  After 
this  oil  ceases  to  distill,  instead  of  heating  with 
fire  heat  to  thicken  the  tar,  the  residue  is  dis- 
tilled in  a  current  of  steam  which  takes  over  the 
remaining  light  oils,  leaving  the  tar  in  the  still  in 
good  condition  for  the  market. 

In  Palmer's  process  the  object  Is  to  obtain  tur- 
pentine only  from  short  pieces  of  wood  by  means 
of  steam  under  pressure.  Here  resort  is  again  had 


of  car  for  use  for  both  purposes,  a  description  of 
it  may  as  well  be  given  here. 

In  the  illustration,  Fig.  38,  Fig.  2  represents  a 
retort,  A,  fitted  with  a  three  rail  track  upon  which 
rests  two  cars.  A  steam  pipe,  E,  sends  steam 
through  the  middle  of  each  car.  This  pipe  is  re- 
newed by  means  of  the  revolvable  joint,  n,  when 
the  cars  are  to  be  taken  out.  Any  excess  pressure 
of  steam  escapes  through  the  lever  safety  valve,  b, 
taking  with  it  the  turpentine  vapor  as  described 
in  Krug's  steam  process.  By  setting  the  retort  in 
a  proper  furnace  the  wood  can  be  destructively  dis- 
tilled and  the  charcoal  be  drawn  out  in  the  cars 
and  rolled  into  a  suitable  air  tight  cooler,  the  vola- 
tile product  escaping  in  the  usual  manner. 

The  special  construction  of  the  car  is  shown  in 


FIG.  38— PALMER'S  PROCESS. 


to  the  use  of  cars  to  transport  the  wood  with  fa- 
cility. Three  rail  or  two  rail  tracks  are  used  in 
the  retort  upon  which  the  specially  constructed 
cars  are  run  in.  The  patent  relates  particularly  to 
the  use  and  construction  of  the  cars.  Money  could 
have  been  saved  by  investigating  other  processes 
.in  use  at  the  time  application  was  made  for  the 
patent.  The  same  idea,  better  in  some  respects, 
had  been  in  use  several  years  before  this  patent 
was  issued.  An  illustration  of  such  a  plant  using 
cars  of  this  kind  for  extracting  the  turpentine  by 
passing  steam  through  a  perforated  pipe,  extend- 
ing through  the  middle  of  a  perforated  car  will  be 
found  elsewhere.  At  this  plant  the  steam  treat- 
ment was  followed  by  destructive  distillation. 
As  the  perforated  car  is  perhaps  the  best  form 


detail  at  Fig.  4.  At  E  is  the  perforated  pipe  fitted 
at  one  end  with  a  funnel  shaped  arrangement,  El, 
and  the  other  end  without  the  same.  By  this  ar- 
rangement when  two  or  more  cara  are  placed  in  one 
retort  the  end  E2  fits  in  the  funnel  shaped  end  of 
El  of  the  other  car,  thus  making  a  loosely  con- 
nected pipe  extending  through  all  the  cars.  The 
framework  of  the  car  is  made  of  slats  of  iron  and 
the  whole  covered  with  wire  netting. 

It  has  been  found  in  practice  at  the  steam  and 
destructive  plant,  before  spoken  of,  where  similar 
cars  were  first1  used  that  there  are  certain  features 
of  construction  necessary  to  make  the  cars  satis- 
factory. 

They  must  be  made  sufficiently  rigid  tbat  the 
wheels  will  not  get  out  of  line,  two  rails  are  better 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


69 


than  three,  the  perforations  in  the  steam  pipe  and 
in  the  netting  must  be  very  large  to  keep  from 
filling  up  with  tar  and  gum,  and  in  making  tar 
should  be  fitted  with  a  device  for  scraping  the  bot- 
tom of  the  retort. 

In  Adams'  process  an  oven  with  a  V-shaped  bot- 
tom is  surrounded  on  the  sides  and  top  with  an 
iron  shell.  At  one  end  of  the  shell  is  a  fireplace 
and  on  the  other  a  brick  flue.  The  space  between 
the  oven  and  outer  shell  is  for  the  fire  gases  to  cir- 
culate, and  by  means  of  partitions  these  gases  are 
led  rearwardly  in  a  zig-zag  manner  to  the  flue  with- 
out touching  the  bottom  of  the  oven.  The  oven  is 
set  horizontally  and  from  various  points  in  the 
bottom  are  tar  pipes.  At  the  top  of  the  oven  are 
several  vapor  pipes  leading  to  a  condenser,  and 


height  ought  to  make  better  tar  than  a  horizontal 
retort,  for  the  reason  that  it  is  not  so  necessary 
to  keep  the  bottom  hot  in  order  to  completely  char 
the  wood.  When  tar  is  vaporized  it  usually  breaks 
up  into  thinner  products  and  leaves  a  deposit  of 
coke.  By  keeping  the  bottom  of  the  retort  cool 
this  vaporizing  of  the  tar  can  be  prevented  to  a 
large  extent.  In  vertical  retorts  of  small  diameter 
only  a  comparatively  small  surface  comprises  the 
bottom,  so  for  this  reason,  in  spite  of  the  difficulty 
of  heating,  a  vertical  retort  is  of  value. 

Several  forms  of  vertical  retorts  have  been  in 


FIG.  39— HESSDL'S  PROCESS. 


one  safety  pipe  connected  with  the  flue  for  the 
escape  of  gas  when  there  is  much  pressure  in  the 
oven. 

Like  all  retort's  where  the  heat  is  not  applied  to 
the  bottom,  it  is  difficult  to  thoroughly  char  the 
wood,  so  when  the  distillation  is  about  finished 
air  is  admitted  through  suitable  openings  in  the 
oven,  which  burns  the  remaining  tar  left  in  the 
wood,  the  products  of  combustion  being  carried 
through  the  safety  pipe  to  the  flue.  The  only  merit 
it  possesses  is  that  it  is  easy  to  get  at  the  tar 
pipes. 

Vertical  Retorts. — Although  a  horizontally  placed 
retort  is  more  easily  heated,  there  are  many  proc- 
esses patented  which  require  a  vertical  retort.  A 
vertical  retort  with  a  diameter  much  less  than  its 


PIG.    40— ROAKE'S    PROCESS. 

use  in  the  hardwood  industry  in  Europe  for  some 
time.  All  these  forms  seem  to  have  given  way 
to  the.  form  shown  in  Fig.  39,  known  as  Hessel's 
Thermo-Boiler,  or  Swedish  Thermo-Boiler.  This  il- 
lustration is  taken  from  the  Consular  reports  of 
1901,  given  by  Consul-General  Mason  at  Berlin. 

A  close  resemblance  to  this  apparatus  will  be 
seen  in  American  processes  patented  since  that 
time.  As  this  form  can  be  readily  used  for  dis- 
tilling pine  wood,  a  description  will  be  here  given. 

The  wood  is  dropped  in  at  Y  into  the  retort  A 
and  the  cover  placed  on.  Tp  make  turpentine  a 


70 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


fire  is  started  at  a  and  superheated  steam  turned 
in  from  pipe  e.  The  turpentine  and  light  oils 
pass  over  through  to  B,  where  the  creosote  falls 
to  Bl,  the  light  oil  following  f  to  the  condenser  C, 
and  thence  into  separate  receivers;  the  gas  escap- 
ing through  E  into  the  air  or  led  to  the  furnace. 
The  tar  formed  falls  to  the  bottom  of  the  retort 
and  flows  out  at  c  into  Bl,  which  acts  as  a  tar  pipe 
for  a  series  of  retorts.  The  charcoal  formed  is 
drawn  out  at  y  or  drawn  out  at  a  door  near  the 
bottom,  b. 

The   first    American    process    for   distilling    pine 
or  other  wood   by  means   of  vertical   retorts  that 


The  next  process,  that  of  Bilfinger's.  Fig.  41,  is 
perhaps  the  most  exploited  of  any  of  those  using 
vertical  retorts. 

The  illustration  shows  the  general  construction, 
3  being  the  retort,  22  a  box  condenser,  31  a  goose- 
neck trap  for  the  gases  which  escape  above  the 
"roof  through  pipe  34.  The  products  of  condensa- 
tion are  divided  into  three  grades  and  each  grade 
carried  into  a  separate  pipe  to  a  storage  tank.  The 
draw-off  valves  from  the  condensers  leading  to 
these  pipes  are  shown  at  32.  The  barrel  25  serves 
the  purpose  of  Roake's  device  just  described,  that 
of  separating  some  of  the  heavier  vapors  from 


FIG.    41—  BILFINGER'S    PROCESS. 


will  be  considered  is  that  of  Roake,  Fig.  40.  The 
process  has  to  do  entirely  with  the  removal  of  the 
heavy  vapors  from  the  lighter  ones  by  condensa- 
tion in  a  special  vessel,  B,  corresponding  to  B, 
Fig.  39.  This  vessel  is  made  very  large,  so  that 
the  vapors  entering  at  the  bottom  from  pfpe  Al 
move  very  slowly,  thus  giving  more  time  for  the 
heavy  vapors  to  condense  and  flow  down  D  into 
D3,  while  the  light  vapors  pass  through  A2  to  the 
condenser  c.  The  trays  n  nl  are  added  so  as  to 
present  more  cooling  surface  to  the  vapors.  It 
can  be  readily  understood  that  this  apparatus 
could  be  used  with  horizontal  retorts. 


the  lighter  ones.  In  practice  a  pipe  was  placed 
at  the  middle  of  the  shell  of  the  retort  connect- 
ing with  the  tar  pipe,  16,  thus  making  another 
separation  of  the  vapors  in  the  retort  itself. 

The  furnace  construction  and  retort  with  heat- 
ing coil  are  shown  also.  The  retort  instead  of 
being  round  is  oval,  and  two  are  set  in  one  fur- 
nace, with  the  fire  door  between.  No  grates  are 
used,  as  the  fires  can  be  better  regulated  without 
them.  At  the  bottom  of  each  retort  at  7  is  a 
man-hole  for  withdrawing  the  charred  wood.  At 
Id  is  a  screen  to  hold  back  the  chips  and  brok- 
en wood,  while  the  tar  flows  on  through  pipe  15 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


71 


to  the  trough  17.  In  practice  conveyors  carried 
sawed  wood  to  the  top  of  the  furnace,  from  whence 
it  is  put  into  the  retort  through  manhole  6.  After 
cnarging  the  retort  the  manhead  is  replaced  and 
tightened  and  a  fire  started  in  the  furnace.  In 
some  plants  steam  is  not  used.  The  temperature 
lo  kept  quite  low  and  very  clear,  white  oil  dis- 
tills over  and  it  is  allowed  to  flow  into  its  proper 
receiver.  As  the  temperature  rises  a  more  and 
more  yellowish  product  is  obtained  and  in  the  lat- 
ter stages  a  bad  odor  and  considerable  gas,  the 


A  plant  of  this  kind  generally  consists  of  ten 
or  more  retorts  set  in  a  row  and  hold  about  one 
cord  each.  A  distillation  usually  takes  36  hours, 
thus  allowing  each  retort  to  be  charged  and  dis- 
tilled four  times  per  week,  starting  Sunday  night 
at  12  M.  N.,  and  ending  Saturday  night  at  12  M.  N. 
The  different  grades  of  oil  thus  produced  are  re- 
distilled and  are  then  ready  for  the  market. 

Of  the  many  plants  erected  to  use  this  process 
all,  or  nearly  all,  have  failed.  Although  like  all 
other  processes,  the  different  by-products  can  be 


FIG.    41— BILFINGER'S    PROCBSS. 


latter  escaping  into  the  air.  By  closing  and  open- 
ing the  proper  valves  at  32  the  different  grades  of 
oil  go  to  their  respective  receivers.  In  the  mean- 
time, most  of  the  resin  and  tar  is  discharged  at  16 
and  flows  from  the  trough  into  a  well.  The  wood 
is  not  thoroughly  charred,  but  the  process  is 
stopped  with  the  making  of  red  wood,  or  terrified 
charcoal.  The  tar  formed  by  this  process  is  of 
very  good  quality,  as  it  is  not  contaminated  with 
the  black  tar  formed  during  the  later  stages  when 
wood  is  completely  charred. 


obtained  from  the  wood  and  of  very  good  quality, 
it  is  not  to  be  expected  that  a  plant  making  only 
turpentine  and  tar  and  taking  36  hours  to  com- 
plete the  operation,  would  be  as  successful  as  a 
steam  process  which  takes  only  from  one  to  six 
hours.  As  with  all  destructive  distillation  proc- 
esses, the  retorts  are  damaged  to  a  great  extent 
by  the  heat  and  are  found  to  leak.  Furthermore, 
a  destructive  distillation  process  that  does  not 
make  salable  charcoal  cannot  succeed  in  competi- 
tion with  a  steam  process,  as  the  tar  produced  by 


72 


THE    UTILIZATION    OP    WOOD    WASTE    BY   DISTILLATION. 


this  method  is  not  of  sufficient  value  to  warrant 
the  expense  of  obtaining  it.  With  charcoal  at  a 
high  price,  a  destructive  plant  might  pay  where 
a  steam  plant  would  not.  This  would  be  particu- 
larly true  in  those  cases  where  wood  costs  more 
than  the  value  of  the  turpentine  produced  from  it. 
The  failure  of  the  different  Bilfinger  processes 
has  had  a  very  depressing  influence  upon  the  wood 
turpentine  business  generally,  which  never  has 
been  very  encouraging,  anyway,  notwithstanding 


the  steam  process,  which  has  proven  satisfactory 
to  him. 

There  are  two  Palmer  processes  using  vertical 
retorts,  the  latest  one  being  shown  in  Fig.  42. 
The  working  of  the  apparatus  can  be  easily  un- 
derstood. Starting  with  the  wood  in  the  retort 
and  the  vapor  pipe  5d  or  5c  at  the  end  of  the  con- 
denser open,  a  medium  fire  is  started  and  steam 
turned  in  from  pipe  12.  The  vapors  of  oil  and  water 
rise  and  pass  out  through  pipe  3,  where  the  tar 


FIG.    42— PALMER'S    PROCESS. 


the  booming  it  has  always  received  each  time  a 
new  patent  is  granted.  The  owners  of  the  plants 
have  themselves  to  blame,  for  in  most  cases  they 
had  their  choice  of  better  and  longer  tried  proc- 
esses. 

Processes  taking  24  hours  or  less  are  now  de- 
manded, and  those  processes  that  cannot  fulfill  the 
conditions  should  not  be  considered.  One  party 
who  used  the  Bilfinger  process  has  now  a  preju- 
dice against  all  destructive  processes,  considering 
them  to  be  total  failures.  He  is  an  adherent  of 


oils  are  supposed  to  condense  at  3a  and  flow  down 
pipe  10  and  the  creosote  to  condense  at  3b  and 
flow  down  pipe  11  and  the  remaining  vapor  passes 
through  condenser  4,  where  part  of  it  is  convert- 
ed into  liquid  form  and  runs  down  5c  or  5d  to  the 
receivers,  1  or  8,  the  uncondensed  gases  escaping 
through  5e.  One  of  the  receivers,  1  or  8,  is  used 
for  the  light  turpentine  oil,  which  comes  over  first, 
and  the  other  for  the  heavier  oil  during  the  later 
stage.  Each  receiver  is  supplied  with  a  filter,  7a 
and  8a,  and  also  with  connections  for  a  supply  of 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


73 


warm  water.  This  warm  water  is  used  as  a  re- 
fining agent  to  remove  some  of  the  impurities.  The 
tar  flows  out  at  the  bottom  after  the  steam  has 
been  cut  off  and  the  heat  raised,  and  finds  its  way 
to  a  sealed  trough,  2a.  The  charcoal  is  taken  out 
at  la. 

This  process,  although  similar  to  the  Bilfinger, 
is  not  as  good.  The  bottom  not  being  well  pro- 
tected, the  tar  is  overheated,  and  what  is  worse, 
the  tar  pipe,  2a,  will  choke  up  and  burn  off  if  set 
as  shown.  The  same  drawbacks  of  the  Bilfinger 
process  relative  to  the  time  of  distilling  apply 
equally  as  well  here. 

Another  process,  evidently  a  modification  of  Bil- 
finger's,  is  that  of  Douglas,  shown  in  Fig.  43.  Two 


lowed  to  flow  through  pipe  25  to  where  it  joins 
pipes  33,  26  and  27.  Any  condensed  matter  can 
thus  flow  down  either  pipe  33  or  26  into  the  bar- 
rel, while  the  uncondensed  vapors  follow  pipe  27 
to  condenser  28,  where  they  are  partially  con- 
densed and  flow  into  a  receiver,  any  uncondensed 
gases  going  up  through  pipe  31.  Pipe  32  carries 
out  any  light  tar  oil  direct  to  the  barrel,  any  light 
vapor  and  uncondensed  gas  going  up  pipe  33 
through  27  to  the  condenser  28,  where  they  are 
separated  and  condensed  in  the  usual  manner. 
The  tar  flows  out  35  into  the  trough  36.  This  proc- 
ess also  has  the  drawbacks  of  the  Bilfinger  proc- 
ess, as  previously  mentioned. 
A  more  elaborate  process  for  the  refining  of 


FIG.   43— DOUGLAS'   PROCESS. 


retorts  are  set  in  one  furnace  and  connected 
with  the  same  series  of  condensers.  In- 
stead of  passing  all  the  vapors  through 
one  condenser  and  separating  them  into 
three  portions  at  the  tail  pipe,  a  separate  con- 
denser is  used  for  each  light  product.  In  operat- 
ing the  wood  is  placed  in  the  retort  and  a  fire 
started  in  the  grate.  No  steam  is  used,  the  va- 
pors rise  on  account  of  the  heat  and  the  light 
vapors  pass  out  near  the  top,  down  pipe  18,  over 
barrel  25-1,  which  receives  any  condensed  creosote 
flowing  down  pipe  24.  The  light  vapors  pass  on 
through  the  condensing  coil  19,  where  they  are 
condensed.  As  the  heat  progresses  the  heavier 
vapors  formed  do  not  rise  as  high,  but  are  al- 


the  vapors  coming  from  the  retort  is  that  of 
Clark  &  Harris.  Chemicals  are  used  to  fix  the  im- 
purities. 

The  object  of  the  patent  seems  to  be  to  protect 
the  inventors  in  a  process  for  the  extraction  of 
pine  oil.  The  claims  state  that  pine  wood  yields 
up  a  small  quantity  of  turpentine  as  an  educt, 
whereas  the  bulk  of  the  light  oil  is  a  product  of 
decomposition  coming  over  when  the  temperature 
reached  240  degrees  to  300  degrees  Fah.  Further- 
more, the  claims  state  that  the  pine  oils  will  not 
distil  over  with  a  low  temperature  steam.  If  this 
were  true,  the  modern  steam  plant  using  steam  at 
5  to  10  Ibs.  pressure  would  yield  only  a  small 
quantity  of  turpentine  when  used  with  fat  pine. 


74 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


However,  actual  practice  shows  15  to  16  gallons 
of  oil  to  the  cord  under  these  conditions,  which 
is  as  good  a  yield  as  when  the  temperature  is 
higher.  The  discussion  of  what  the  products  and 
educts  from  pine  wood  are  will  be  left  for  another 
chapter. 

This  process  is  illustrated  in  Fig.  44.  To  carry  . 
out  the  operation  the  retort  a  is  filled  with  pine 
or  fir  wood  and  heated  gradually  in  any  suitable 
manner.  During  the  distillation  tar  is  formed  and 
is  best  drawn  off  from  the  bottom  of  the  retort 
as  fast  as  it  is  formed,  the  tar  pipe,  a2,  being  al- 
ways open. 


within  the  condenser  d,  whereby  the  temperature 
therein  can  be  regulated  to  prevent  condensation 
of  the  pine  oil  vapors.  The  open  steam  pipe  el, 
also  serves  to  help  along  the  vapors  and  to  clean 
out  the  apparatus  when  necessary.  The  condensate 
in  the  condenser  d  will  in  actual  operation  pref- 
erably be  kept  at  such  level  that  the  live  steam 
from  pipe  el  will  play  over  its  surface.  From  the 
condenser  d  the  vapors  pass  through  the  pipe  to 
condenser  fl,  where  more  condensation  of  heavy 
vapors  take  place.  These  flow  back  to  d,  while 
the  lighter  vapors  pass  down  f2  through  the  per- 
forated pipe  f3  into  the  box  g  containing  milk 


FIG.    44— CLARK    &    HARRIS    PROCESS. 


The  vaporized  products  of  the  distillation  pass 
into  the  air  condenser  d,  into  the  bottom  of  which 
the  heavy  oils,  acetic  acid,  water,  etc.,  precipitate 
and  from  here  they  can  be  drawn  off  through  pas- 
sage d3.  It  is  advisable,  however,  to  let  them 
stay  a  short  time  in  the  bottom  of  the  condenser, 
in  order  that  the  heat  of  the  vapors  may  evaporate 
any  pine  oils  contained  therein,  which  would  other- 
wise be  carried  off  with  the  heavy  products  in  case 
they  were  withdrawn  immediately.  However,  the 
best  way  to  guard  against  possible  loss  of  pine  oil 
through  condensation  at  this  point  consists  in 
providing  open  and  closed  steam  pipes  el  and  d2, 


of  lime  or  other  forms  of  alkali,  which  absorbs  the 
acetic  acid,  etc.  Any  carbonates  formed  would, 
of  course,  be  decomposed  by  any  excess  of  acetic 
acid  to  form  acetates.  The  unabsorbed  vapors 
then  pass  to  a  similar  box  or  tank  i,  containing 
a  solution  of  caustic  soda  of  preferably  1.21  sp.  gr. 
This  alkali  absorbs  the  heavy  oils,  forming  a  solu- 
ble disinfectant.  The  vapors  pass  up  p  into  the 
air  condenser  r,  where  the  pine  oils  are  con- 
densed, while  the  light,  bad-smelling  oils  pass  to 
the  condenser  rl  and  are  liquified.  A  condenser 
pi,  is  used  to  further  condense  any  pipe  oil  vapor 
not  going  beyond  r.  The  gases  are  tapped  by  the 


THH    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


75 


U,  r3  and  q2,  and  the  pump  S  draws  the  gases 
away  from  the  apparatus  by  means  of  pipes,  ul 
and  t2.  The  charcoal  is  drawn  out  at  the  door  XI. 
There  is  not  much  doubt  that  this  process  cUn 
produce  a  clear,  white  oil  during  part  of  the  dis- 
tilling process,  but  it  would  seem  that  the  process 
would  require  a  great  deal  of  care  in  order  to  make 
all  parts  of  the  apparatus  work  together,  and  also 
it  appears  that  it  would  be  necessary  to  distil 
slowly.  The  industry  requires  retorts  that  will 
extract  the  oils  rapidly  like  the  steam  process 
does,  so  that  there  will  be  but  little  expense  for 
plant  equipment.  One  retort  with  the  steam  proc- 


The  operation  of  the  device  is  as  follows:  The 
wood  is  placed  in  the  retort  and  heat  applied. 
The  vapors  pass  through  i  into  the  creosote  cham- 
ber j,  where  the  creosote  separates.  The  light  va- 
pors pass  to  the  condenser  C,  and  the  oil  and 
water  formed  collect  in  D.  The  oil  rises  to  the 
top  of  the  water  and  overflows  into  the  refining 
still,  E.  Here  the  usual  refining  process  takes  place 
by  distilling  with  steam  coming  from  the  boiler,  G. 
The  steam  and  oil  vapor  liquify  in  the  condenser, 
F,  and  are  collected  and  separated  in  the  usual 
manner. 

The  creosote  that  separated  in  j  is  allowed  to 


FIG.    45— SIBBITT    &    McLEAN. 


ess  will  do  as  much  in  one  hour  as  with  this 
process  in  twelve.  It  is  more  economical  to  have 
refining  stills,  which  are  very  small  in  comparison 
to  the  amount  of  oil  treated,  than  to  have  refin- 
ing retorts. 

Another  process  using  vertical  retorts  is  that  of 
Sibbitt  &  McLean.  In  addition  to  distilling  the 
wood,  an  apparatus  is  added  to  distil  the  tar. 

In  the  illustration,  Fig.  45,  A  is  a  retort  in  which 
the  wood  is  distilled.  The  furnace  construction  is 
of  the  usual  type.  At  the  bottom  of  the  retort 
are  water  pipes,  h,  for  cooling  the  tar,  and  a 
strainer  b4,  to  keep  the  dirt  and  chips  out  of  the 
tar  pipe. 


flow  down  pipe  v  into  the  creosote  refining  still, 
K.  Here  the  creosote  is  distilled  by  means  of 
fire  heat  and  condensed  in  the  usual  manner,  the 
heavy  tarry  products  remaining  in  the  still  and 
being  drawn  into  w  when  necessary. 

The  tar  flows  down  pipe  t  to  a  series  of  con- 
densing tanks,  I  and  J,  from  which  the  tar  can 
be  run  into  the  tar  still,  H.  Here  the  light  oils  are 
driven  off.  Any  water  remaining  in  the  tar  can 
be  separated  and  tar  sent  to  the  still,  M,  for  fur- 
ther treatment.  Here  the  tar  itself  is  distilled, 
light  oil  of  tar  vaporizing  while  the  pitch  and 
heavy  oil  remain  in  the  still  from  whence  they 
can  be  withdrawn. 


76 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


The  operation  of  the  process  can  be  understood 
from  the  description  of  the  more  simple  ones  al- 
ready given.  This  treatment  of  the  tar  would  be 
found  to  be  very  unsatisfactory. 

One  hears  so  much  about  European  methods  of 
distilling  resinous  woods,  that  the  following  Rus- 
sian method  is  described  to  show  that  American 
processes  are  as  good  as  European. 

The  illustration,  Fig.  46,  shows  Friis's  process. 
The  retort  is  made  of  iron,  with  a  V-shaped  bottom, 
surrounded  with  a  brick  chamber  which  contains 
the  flue  gases.  The  grates  are  at  c  at  both  ends 
and  the  fire  gases  -are  made  to  travel  around  the 


In  Ross  &  Edwards'  process  is  found  a  combina- 
tion of  the  old  principles  of  the  Swedish  oven  pre- 
viously illustrated,  Fig.  8,  and  the  more  modern 
ideas  of  fractional  condensation  of  the  vapors  to 
remove  the  creosote. 

In  the  illustration,  Fig.  47,  the  retort  is  repre- 
sented at  1.  The  wood  is  set  on  the  grate,  4,  and 
ignited  and  the  carbonization  carried  on  by  inter- 
nal combustion  the  same  as  with  an  ordinary 
charcoal  kiln.  The  vapors  escape  through  pipe 
6  Fig.  2,  down  pipe  7  Fig.  3,  where  they  enter  the 
hydraulic  main,  5.  This  main  is  sprinkled  with 
water  by  means  of  perforated  pipe,  8a.  This  cool- 
ing causes  the  heavy  oils  to  separate  while  the 
light  vapors  pass  up  pipe  9  through  10  Fig.  2,  to 
chamber  11,  where  they  strike  the  baffle  plate,  13, 
and  pass  under  and  up  the  condenser  pipe,  15. 
The  chamber  11  is  used  to  further  purify  the  va- 
pors. The  gas  formed  passes  out  of  pipe  19.  The 


FIG.  46— FRIIS  PROCESS. 


FIG.  46— FRIIS  PROCESS. 


top  and  sides  by  means  of  partitions.  To  help  heat 
the  interior  of  the  retort,  flues  d  pass  through  the 
retort  at  several  places. 

The  tar  and  resin  formed  flow  through  pipes  at 
the  bottom,  while  the  light  oils  pass  through  pipe 
6  to  a  series  of  box  condensers,  f,  fl,  etc.,  surround- 
ed by  water,  the  very  light  vapors  being  condensed 
by  the  worm  condenser  1.  The  liquid  collected  in 
the  various  box  condensers  is  drawn  into  suitable 
tanks  for  storage.  The  charcoal  is  drawn  out 
through  suitable  openings  at  the  bottom  of  the  re- 
tort. The  operation  of  this  process  is  readily  un- 
derstood by  pine  wood  distillers. 


tar  is  drawn  off  at  25  and  the  charcoal  removed  at 
3.  With  a  kiln  this  latter  would  probably  be  of 
poor  quality. 

The  writer  would  suggest  that  if  anyone  wishes 
to  use  a  kiln  heated  internally  that  instead  of  us- 
ing fat  wood  for  fuel,  which  is  actually  done  in 
the  above  process,  it  would  be  better  to  place  a 
similar  kiln  to  one  side  of  the  one  holding  the  fat 
wood.  By  placing  cheap,  low  yielding  wood  in  this 
kiln  and  connecting  it  with  the  one  containing  the 
fat  wood  the  hot  gases  formed  by  burning  the 
wood  in  the  first  kiln  could  be  led  through-  the 
wood  in  the  second  kiln,  thus  causing  this  wood 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


77 


to  distill  without  much  loss  of  valuable  products. 
Of  course,  this  increases  the  cost  of  a  plant,  but 
the  saving  in  yield  of  products  would  warrant  it. 
One  great  objection  to  the  kiln  form  is  that  both 
the  fire  gases  and  vapors  from  the  wood  must  pass 
through  the  condenser,  wh-ich  must  necessarily  be 
made  larger  and  require  more  cooling  water.  When 
heated  from  the  outside  the  fire  gases  go  up  the 
stack. 

As  a  refining  method  this  process  can  be  com- 
pared easily  with  the  others  previously  consid- 
ered. The  general  principles  are  the  same  and  are 
carried  out  in  a  similar  manner.  None  of  these 
retort  refining  processes,  except  that  of  Clark  and 


FIG.  47— ROSS  &  EDWARDS  PROCESS. 

Harris,  seem  to  take  into  consideration  that  when 
the  oil  first  begins  to  distill  the  creosote  sepa- 
rators being  cold,  condense  considerable  turpentine 
which  usually  finds  its  way  to  the  creosote  tank. 

Probably  the  best  of  the  vertical  retort  processes 
is  that  of  Mathieu,  Fig.  48.  It  was  devised  by  a 
man  of  considerable  experience  in  the  industry  in 
this  country  and  in  France.  A  resemblance  is  noted 
to  the  French  process  shown  at  Fig.  10,  Chapter  IV. 

In  this  method  a  process  is  used  of  quickly 
withdrawing  the  charcoal  without  waiting  for  the 
furnaces  to  cool  down.  At  AA,  Fig.  48,  is  repre- 
sented a  series  of  retorts  made  of  fire  clay  or  iron. 
Covering  the  top  of  the  retort  is  the  head,  B. 


The  operation  is  simple.  The  basket  D  is  filled 
with  wood  and  carried  over  the  retort  in  the  man- 
ner shown  and  lowered  into  the  retort.  The  cover 
being  placed  on,  the  distillation  is  proceeded  with 
in  the  ordinary  manner,  the  light  oils  passing  out 
at  b  and  the  tar  flowing  out  at  b2. 

The  illustration  shows  how,  after  the  wood  is 
charred,  the  basket  containing  the  charcoal  is 
drawn  up  into  the  cooler,  J,  where  the  air  is  ex- 


FI&.l. 


/*"> 


FIG.    4i— MATHIEU'S    PROCESS. 

eluded.  This  operation  with  one  cord  retorts  oc- 
cupies less  than  five  minutes.  The  cooler  and  its 
contents  are  then  placed  to  one  side  after  the  bot- 
tom cover  has  been  put  on  to  exclude  the  air,  and 
a  spray  of  water  from  pipe  P  allowed  to  flow  over 
the  surface  of  the  cooler,  escaping  at  the  overflow 
pipe  m  at  the  bottom. 

This  process  is  readily  understood  and  is  compar- 
able  with   those   processes   using   cars   in  a  hori- 


78 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


zontal  retort.  Both  processes  offer  equal  advan- 
tages. The  vertical  retort  ought  to  make  better 
tar,  while  the  horizontal  retort  ought  to  be  more 
easily  heated.  A  horizontal  retort  has  the  advan- 
tage that  its  sections  are  not  entirely  dependent 
upon  the  rivets  to  hold  them  in  position,  whereas 
in  a  vertical  retort  when  hot  there  is  a  tendency 
to  sheer  off  the  rivets,  owing  to  the  weight  of  the 
superimposed  sections. 
A  process  used  on  the  Pacific  coast  to  a  limited 


the  center  of  the  pan,  through  which  they  fall  to 
the  bottom  of  the  retort.  Through  this  circular 
space,  which  extends  through  the  middle  of  the 
basket,  a  water  pipe  is  led  branching  below  each 
section  as  at  30-30.  These  branches  are  perforated 
and  serve  as  a  means  of  quenching  the  charcoal 


FIG.     49— JEWETT     PROCESS. 


FIG.    50— FIVEASH    PROCESS. 


extent  is  that  of  Jewett,  Fig.  49.  The  principle 
is  very  similar  to  Matbieu's,  but  is  more  compli- 
cated. It  consists  of  a  vertical  retort,  16,  pro- 
tected at  the  bottom  with  fire  brick,  9,  and  a  metal- 
lic shield,  13,  surrounding  the  upper  portions.  A 
basket  is  used  as  in  Mathieu's  process,  but  it  is 
a  complicated  affair  arranged  in  sections  so  as 
to  stand  the  wood  on  end.  Under  each  section  is 
a  solid  sheet  iron  pan,  28,  to  receive  the  products 
of  the  distillation,  and  to  direct  them  to  a  hole  in 


after  the  distillation  is  finished.  All  the  products 
of  the  distillation  go  out  at  the  bottom  and  are  led 
to  condensers  and  tanks  as  required. 

This  process,  although  patented  a  couple  of  years 
after  Mathieu's,  is  not  as  good.  It  is  bad  practice 
to  wet  charcoal,  as  it  causes  it  to  powder  easily. 
In  practice  it  will  probably  be  found  that  the  metal- 
lic shield  will  warp  and  burn  out  and  probably 
change  the  retort  so  much  as  to  prevent  the  en- 
trance of  the  basket.  Then  the  basket  itself  is  not 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


79 


as  good  as  the  simple  one  used  in  Mathieu's  proc- 
ess. This  latter  form  answers  all  the  requirements 
necessary,  and  with  the  cooler  forms  a  very  satis- 
factory combination.  The  process  offers  an  advan- 
tage in  that  it  takes  off  all  the  products  of  distilla- 


It  is  a  self-contained  form  made  out  of  steel. 
The  retort  is  at  4  and  is  heated  by  burning  fuel 
placed  on  the  grates,  12.  The  products  of  com- 
bustion pass  upward  through  the  flues,  18.  To  cool 
the  bottom,  the  chamber,  15,  is  filled  with  water, 
the  steam  formed  passing  through  17  into  the  re- 
tort. At  the  top  of  the  retort  is  a  charging  door, 
19,  for  the  wood  and  a  discharging  door,  20,  for 
the  charcoal.  The  volatile  matters  pass  out  through 


FIG.    51— WILLIAMS    PROCESS. 


FIG.     52— SNYDER'S    PROCESS. 


tion  from  the  bottom,  thus  preventing  in  a  measure 
any  possible  overheating. 

In  the  Fiveash  process,  Fig.  50,  an  attempt  is 
again  made  of  heating  the  contents  of  the  retort  by 
means  of  flues.  The  writer  does  not  believe  that 
this  apparatus  is  in  use,  but  it  may  be. 


26  to  the  condenser,  the  tar  flows  out  at  the  bot- 
tom at  21,  while  the  gas  escapes  through  22  and  31. 
Apparatus  of  this  kind  has  been  tried  since  Reich- 
enbach's  time,  but  for  some  reason  does  not  give 
the  satisfaction  that  it  seems  it  ought.  The  ac- 
tion of  dry  heat  on  flues  might  be  compared  to  the 


80 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


heating  of  boiler  flues  when  there  is  no  water  in 
the  boiler.  In  this  process  one  end  is  protected 
to  some  extent  by  the  water  at  the  lower  joints,  but 
not  at  the  top.  It  is  difficult,  also,  to  draw  the 
charcoal  and  fill  with  wood.  If  it  were  not  for  the 
bad  effect  of  the  heat  on  the  flues  this  idea  of 
heating  the  middle  of  the  retort  would  be  a  good 
one. 

Another  Pacific  coast  process  is  that  of  Will- 
iams, Fig.  51.  Steam  under  pressure  is  used  to 
carry  off  the  light  oils,  and  the  residue  distilled 
by  fire  heat. 

In  the  illustration  1  is  a  steel  retort  set  vertically 
in  a  furnace.  The  bottom  is  protected  by  a  shield, 


and  tar  oil  vapors  pass  through,  while  the  tar  is 
drawn  off  into  a  receptacle,  13a,  at  the  bottom. 
To  regulate  the  temperature  means  are  provided 
for  admitting  cooling  water  through  pipe  26,  the 
hot  water  returning  through  pipe  25.  By  opening 
the  door  the  charcoal  is 'allowed  to  fall  into  cooler, 
23,  which  is  covered  over  to  exclude  the  air. 

This  process  seems  to  have  been  well  devised, 
although  the  necessity  of  so  many  perforated  steam 
and  vapor  pipes  is  not  so  apparent.  The  arrange- 
ment for  getting  at  the  bottom  of  the  retort  is 
especially  to  be  commended,  as  the  tar  often 
blocks  the  pipes.  The  wood,  though,  must  not  be 
allowed  to  get  down  too  far  or  it  will  not  thor- 


FIG.    53— COPILOVICH. 


18.    At  the  bottom  of  the  retort  is  a  door  for  re- 
moving the  charcoal. 

The  operation  of  the  process  is  simple.  The 
wood  in  short  lengths  is  dropped  through  open- 
ings 2,  2,  at  the  top,  and  the  openings  covered. 
Steam  is  turned  in  through  pipe  28  until  the  de- 
sired pressure  is  reached  and  the  excess  steam  al- 
lowed to  escape  through  valve  32  at  the  top.  The 
steam  carrying  with  it  the  oil  vapors  passes 
through  the  perforations  at  6  before  it  reaches  the 
exit  valve.  After  passing  the  valve  the  vapors 
follow  pipe  4  and  are  condensed  in  the  usual  man- 
ner. Any  resin  formed  is  drawn  off  from  time  to 
time  through  the  bottom  valve.  13.  After  the  light 
oils  are  distilled  the  steam  is  turned  off  and  the 
wood  heated  by  means  of  the  fire  in  the  furnace. 
The  vapor  valve  30  is  opened  wide  and  the  creosote 


oughly  char.  In  taking  the  charcoal  out  from  a 
large  retort  it  makes  it  necessary  to  place  the  re- 
tort and  furnaces  rather  high  in  order  to  allow 
room  for  the  cooler  underneath. 

Another  process  using  vertical  retorts  supplying 
means  for  withdrawing  the  tar  without  heating 
the  bottom  is  that  of  Snyder,  Fig.  52. 

The  wood  is  put  in  a  container,  D,  enclosed  in  a 
brick  furnace.  This  furnace  is  heated  by  electric- 
ity or  other  means,  no  heat  being  applied  to  the 
bottom  of  the  retort.  The  container,  or  retort,  D, 
has  a  perforated  bottom  so  that  when  the  bottom 
of  the  furnace,  a,  is  closed  the  vapors  can  pass 
through  pipe,  g,  to  a  condenser.  The  charcoal  is 
removed  by  lowering  D  on  to  a  suitable  car  with- 
out waiting  for  the  furnace  to  cool  down. 

This  method  doesn't  show  any  advantages  over 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


81 


Williams'  process,  as  in  the  latter  all  the  vapors 
can  escape  at  the  bottom  if  desired.  The  method 
of  raising  and  lowering  seems  to  be  much  more 
awkward  than  putting  it  in  at  the  top.  As  to  the 
effectiveness  of  electric  heaters  definite  statements 
will  not  be  made  here.  They  are  rather  expensive 
in  other  lines  of  industry,  and  it  is  to  be  expected 
that  such  would  be  the  case  here.  However,  as  with 
all  the  different  pine  distilling  processes,  great 
claims  are  made.  The  statement  is  made  that  a 
current  of  a  thousand  amperes  having  a  potential 
of  two  hundred  volts  gives  satisfactory  results  for 
a  retort  holding  one-half  a  cord  of  wood.  Of 
course,  with  larger  retorts  heated  from  the  out- 
side, it  would  take  relatively  more. 

Another  process  devised  to  allow  the  tar  to  es- 
cape without  undue  heating  is  that  of  Copilovich, 
exploited  for  use  with  Norway  pine  in  Minnesota, 
Fig.  53. 

The  retort  6  is  set  in  a  brick  furnace.  The  wood 
is  put  in  at  the  top  and  a  fire  started  in  the  furnace. 
The  light  vapors  pass  through  10  to  a  creosote 
condenser,  11,  and  the  uncondensed  vapors  pass 
to  the  condenser  13  and  thence  to  the  receiver,  15. 
The  tar  and  heavy  vapors  pass  out  at  the  bottom, 
the  tar  going  to  the  tank,  16,  and  the  vapors  and 
gases  to  condenser,  18.  No  arrangement  seems  to 
be  made  for  the  separation  of  the  gas,  so  this 
would  come  out  with  the  vapors  and  enter  tanks, 
15  and  19,  and  would  be  apt  to  explode  if  brought 
in  contact  with  a  flame.  The  charcoal  is  with- 
drawn through  a  door  at  the  bottom  on  the  side. 

A  Swedish  process  using  such  a  form  of  retort 
was  experimented  with  for  a  time  in  Mississippi, 
but  for  some  reason  a  larger  plant  was  not  built. 

Denny's  process  provides  a  vertical  retort  pro- 
tected on  the  sides  with  sheet  asbestos  and  on 
the  bottom  with  a  double  bottom  containing  sand. 

In  the  illustration,  Fig.  54,  A  represents  the  re- 
tort fitted  with  the  usual  exits  for  vapors.  The 
wood  enters  through  the  top  door,  5,  and  the  light 
vapors  pass  out  through  pipe  21  to  a  suitable  con- 
denser and  the  heavy  vapors  and  tar  flow  out 
through  the  pipe,  20. 

The  furnace  is  heated  with  wood  or  other  fuel 


and  the  flames  strike  against  the  asbestos  lagging, 
5-1,  which  protects  the  retort  from  blistering.  The 
flues  are  so  arranged  that  the  flames  are  deflected 
from  a  straight  course  by  means  of  a  baffle,  11, 
thus  causing  the  retort  to  be  heated  more  effective- 
ly. To  protect  the  bottom  sand  is  placed  in  the 
space,  14,  between  plates  12  and  13.  The  charcoal 
produced  is  drawn  out  at  18. 

There  are  doubtless  many  patents  now  being 
applied  for  that  will  be  issued  shortly.  Probably 
all  of  them  will  resemble  more  or  less  closely  some 
of  those  herein  described,  hence  readily  under- 
stood. 

It  will  be  seen  that  some  of  the  essential  require- 


FIG.    54— DENNY'S    PROCESS. 

ments  of  processes  of  these  kinds  must  be,  first,  a 
good  furnace  constructed  to  obtain  the  greatesf 
heat  from  the  smallest  amount  of  fuel;  second, 
proper  distribution  of  the  flame  so  as  not  to  burn 
the  retort  at  one  place;  third,  proper  position  of 
the  retort  so  that  all  the  wood  contained  therein 
can  be  thoroughly  charged;  fourth,  accessibility  of 
parts  for  repairs;  fifth,  good  arrangements  for 
drawing  off  the  tar  without  choking  the  pipe  or 
burning  the  tar;  sixth,  rapid  removal  of  the  char- 
coal produced  so  as  to  save  the  heat  of  the  fur- 
nace; seventh,  rapid  charging  of  the  retort  and 
quick  distilling  methods  for  obtaining  good  prod- 
ucts, and,  above  all,  eighth — an  absolutely  essen- 


82  THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


FIG.  55A— THE  KRUG  STEAM  PROCESS— SHOWING  RETORTS. 


FIG.  55B— THE  KRUG  STEAM  PROCESS,  SHOWING  CONDENSERS 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


83 


tial  condition — the  production  of  salable  products. 

An  illustration  of  a  steam  process  In  actual  opera- 
tion is  shown  at  Fig.  55.  The  retorts  are  enclosed 
in  brickwork  so  that  the  residue  could  be  distilled 
if  required.  At  Fig.  56  is  shown  a  steam  and  de- 
structive distillation  plant,  using  cars  in  large  re- 
torts. 

Any  form  of  retort,  if  it  be  nothing  but  a  piece 
of  water  or  gas  pipe  closed  at  both  ends  with  an 
exit  for  vapors,  will  make  oil  from  resinous  woods, 
when  heated  in  the  proper  manner.  This  is  the 
reason  that  there  are  so  many  processes.  Some 
form  of  retort  is  designed  and  erected  and  dis- 
tilled products  are  obtained  in  quantity,  and  the 
problem  is  supposed  to  be  solved.  But  some  of 


these  processes  must  be  more  economical  in  opera- 
tion than  others,  and  an  attempt  is  expected  to  be 
made  by  the  Forest  Service  of  the  relative  value 
of  each,  and  also  which  if  any  are  sufficiently  eco- 
nomical. When  proper  tests  are  applied  a  great 
many  of  the  processes  now  being  exploited  will 
disappear,  and  the  sooner  the  better  for  interested 
parties  who  might  wish  to  invest. 

Special    Retorts   and    Processes. 

Some  of  the  processes  which  are  to  be  described 
under  the  above  heading  might  have  been  de- 
scribed under  steam  or  destructive  distillation 
processes,  but  certain  features  connected  with 
them  make  it  advisable  to  consider  them  separate- 


FIG.    56— STEAM   AND   DESTRUCTIVE   PROCESS,    USING   COOLERS   AND  CARS. 


84 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


ly.  This  is  especially  true  of  rotary  and  portable 
apparatus. 

Rotary  Processes. — As  has  been  stated,  wood, 
being  a  non-conductor  of  heat,  it  is  difficult  to  heat 
the  middle  of  an  ordinary  retort  to  the  same  de- 
gree of  temperature  as  the  shell.  This  feature 
is  more  apparent  when  the  wood  is  in  a  finely 
divided  state  such  as  saw  dust.  Consequently 
when  the  turpentine  is  extracted  in  the  steam 
process,  the  residue  cannot  be  destructively  dis- 
tilled in  an  ordinary  retort,  as  it  seems  to  be  ex- 
tremely difficult  to  heat  the  saw  dust  sufficiently 
to  distill  it,  except  at  the  edges  of  the  retort. 

With  hardwood  saw  dust,  attempts  were  made 
to  distill  it  with  superheated  steam,  but  it  took 
so  much  steam  to  carbonize  that  the  condensed 
water  diluted  the  distillate  of  pyroligneous  acid 
and  wood  alcohol  so  much  that  the  extra  evapora- 
tion necessary  to  make  acetate,  made  the  process 
unprofitable.  Steam  has  the  advantage  over  direct 
heat  as  applied  to  a  large  closed  retort,  in  that 
it  can  be  applied  to  the  inside  while  direct  heat 
is  usually  limited  to  the  outside,  except  in  a  few 
cases.  The  feature  of  diluting  the  pyroligneous 
acid,  which  is  noticed  with  the  distillation  of 
hardwood,  with  steam  is  not  objectionable  when 
distilling  pine  wood,  as  this  portion  of  the  distil- 
late is  usually  not  saved  anyway,  and  most  of 
the  oils  and  the  tar  are  nearly  insoluble  in  water 
and  can  thus  be  separated  by  gravity.  Large 
quantities  of  steam,  though,  are  costly. 

A  stationary  retort  ought  to  cost  less  than  a 
rotary  one  and  when  working  for  turpentine  alone, 
unless  the  difference  in  yield  in  a  given  time  would 
pay  for  the  difference  in  the  initial  cost,  the  ro- 
tary retort  will  find  no  practical  use.  In  the  case 
of  steaming  pine  wood  for  turpentine,  it  is  claimed 
by  those  interested  that  as  much  as  25  per  cent 
more  turpentine  can  be  obtained  in  a  given  time, 
and  if  such  proves  to  be  the  case,  rotary  retorts 
will  probably  supersede  the  stationary  ones.  At 
the  present  time  stationary  ones  have  the  field, 
although  one  or  two  rotary  retorts  are  in  opera- 
tion and  giving,  as  is  claimed,  better  satisfaction. 

In  destructive  distillation,   the   rotary   retort  is 


one  of  the  most  feasible  ways  of  distilling  saw 
dust,  either  hardwood  or  pine,  if  such'  be  neces- 
sary. With  the  latter  not  much  would  be  gained, 
as  pine  saw  dust  makes  very  poor  tar  and  char- 
coal. 

By  using  rotary  retorts  in  a  proper  manner,  the 
author  believes  a  better  utilization  of  waste  wood 
can  be  made,  particularly  of  medium  fat  knots 


W////////////////////////M 


FIG.     57— BERRYS'     PROCESS. 

such  as  cannot  be  used  in  the  ordinary  steam 
process  on  account  of  the  cost  of  gathering  being 
more  than  the  amount  received  for  the  turpentine 
produced.  This  is  one  case  where  a  destructive 
process  may  be  better  than  steam. 

As  grinding  the  wood  caused  such-  a  great  sav- 
ing of  time  in  the  steam  process,  so  it  may  be 
expected  that  a  great  saving  of  time  will  be  oc- 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


85 


casioned  when  ground  wood  is  destructively  dis- 
tilled, provided  the  heat  for  this  purpose  can  be 
as  effectively  applied  as  it  is  by  using  steam  in 
the  steam  process.  This  is  the  result  expected 
with  the  special  saw  dust  distilling  apparatus 
herein  described,  especially  the  rotary  retorts. 
All  manner  of  forms  of  rotary  retorts  have  been 
designed  so  as  to  cover  all  possible  modifications, 
so  that  although  many  patents  will  be  applied  for 
when  the  success  of  this  form  of  apparatus  is 


retort  with  an  arrangement  at  K  for  leading  off 
the  vapors  to  pipe  L,  the  tar  formed  dropping  to 
N  and  the  light  oils  passing  up  M  to  the  con- 
denser Q.  A  trap  at  g  holds  back  the  gas  which 
escapes  through  S  to  the  furnace.  The  retort  is 
beated  in  the  ordinary  manner  as  shown.  In  Fig. 
3  is  shown  a  cross  section.  Here  the  retort  13 
represented  at  B;  and  at  one  end  it  is  connected 
with  a  shaft  leading  to  the  pulley  D.  The  other 
end  is  supported  by  the  head  G  from  which  a 


27 — Feed    screw. 
11 — Flue. 


FIG.    58— SPURRIER'S  PROCESS. 


O— Exit   for   vapors. 
P — E~xit    for    charcoal. 


demonstrated,  only  a  few  of  them  can  possibly  be 
valid. 

The  rotary  retort  is  supposed  to  be  the  product 
of  the  past  few  years,  but  it  will  be  noticed  by 
what  follows  that  several  attempts  have  been 
made  in  this  country  as  well  as  in  Europe  to  use 
such  in  distilling  hardwood  «aw  dust. 

The  first  patent  noticed  by  the  author  is  that  of 
Berry,  Figure  57.  This  contrivance  was  devised 
to  utilize  shells  of  cocoanuts  and  seeds,  etc.,  and 
for  wood.  The  exact  arrangement  needs  descrip- 
tion, as  the  illustration  is  not  so  easily  understood. 
Observing  Fig.  1,  we  have  apparently  an  ordinary 


tubular  shaft  extends  into  the  retort.  Turning 
on  the  end  of  this  shaft  is  the  spider  frame  F 
connected  with  the  retort.  The  head  G  being 
stationary,  it  is  advisable  to  make  a  good  joint 
between  the  retort  and  head,  otherwise  air  might 
enter  or  gas  escape  according  to  the  pressure. 
An  exhaust  is  usually  used,  consequently  any  gas 
drawn  in  would  probably  be  fire  gases,  containing 
little  oxygen,  so  little  damage  would  be  done  if 
the  head  is  not  absolutely  tight.  A  stationary  per- 
forated pipe  H  is  added  in  order  to  quench  with 
steam  or  water  the  charcoal  formed. 

It  will  be  noticed  that  K  is  removable  and  is 


86 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


placed  over  a  and  that  e  is  also  removable  and 
is  placed  over  the  opening  b.  The  opening  a  is 
for  filling  the  retort  and  b  for  withdrawing  char- 
coal. The  regular  operation  is  the  same  as  for 
a  stationary  retort,  except  that  the  retort  is  slow- 
ly turned,  thus  causing  each  particle  to  be  evenly 
heated. 

A  more  elaborate  retort  is  used  in  Spurrier's 
process,  Fig.  58,  for  distilling  hardwood  sawdust*. 
This  consists  of  two  helices,  one  working  inside 
of  the  other  so  as  to  send  the  sawdust  in  opposite 
directions.  The  retort  is  heated  by  fire  gases 
led  by  suitable  flues  around  the  retort  with  a 
large  flue  leading  through  the  middle  of  the  re- 
tort. Although  such  a  retort  might  be  suitable  in 
distilling  turpentine  from  pine  saw  dust,  it  is 


much  too  expensive  in  comparison  with  other 
processes.  Another  process  using  rotary  retorts 
is  that  of  Larsen,  also  used  on  saw  dust.  Owing 
to  the  ease  with  which  a  slight  modification  may 
be  made  on  an  invention  and  a  patent  obtained, 
the  inventor  of  this  process  shows  six  different 
modifications  of  the  same  principle.  Considerable 
ingenuity  is  shown  in  each  modification  and  a 
complete  understanding  of  the  conditions  of  dis- 
tilling are  implied.  Two  different  forms  are  indi- 
cated; one  in  which  the  retorts  is  encased  in  brick 
work  and  the  other  a  self-contained  form.  Only 
the  two  types  will  be  described.  Fig.  1  in  Fig.  59 
represents  the  retort  set  in  masonry.  The  retort 
is  at  A  and  rotates  on  a  a. 

The  fire  gases  starting  from  the  grate  pass  to 


///^/////////^^^ 


FIG   59— LARSEN'S   PROCESS. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


87 


the  chamber  L,  thence  follow  the  course  of  the 
arrows  through  B,  then  back  through  K  to  the 
chimney.  The  distilled  vapors  escape  through  R, 
which  is  turned  up  so  as  to  be  above  the  material 
in  the  retort.  The  material  is  dropped  through 
the  brick  work  above  into  manhole  g  (shown  at 
the  bottom)  and  when  charred  is  drawn  out  at 
the  bottom  through  the  manhole  g  by  the  action 
of  the  right  and  left  hand  screw  conveyer  S,  oper- 
ated from  the  outside  at  e.  The  vanes  b  rotate 
with  the  retort  and  help  spread  the  material. 

The  other  form  shown  at  Fig.   3,  4  and  5,  Fig. 
59,  is  self-contained.    The  one  above  could  be  made 


These  devices  are  well  designed  to  overcome 
the  difficulty  of  heating  the  retort;  As  arranged, 
the  whole  retort  revolves,  flues  and  all. 

One  feature  of  machine  design  is  the  ac- 
cessibility of  parts  for  repairs.  Unless  the  above 
retorts  are  very  large,  one  who  is  acquainted  with 
the  destructive  action  of  heat  when  wood  is  dis- 
tilled can  readily  understand  that  great  trouble 
might  arise  from  the  use  of  such  retorts.  Another 
difficulty  would  probably  be  the  warping  and 
bending  of  the  flues  under  the  effect  of  the  heat. 
A  further  disadvantage  is  that  in  destructive  distil- 
lation, every  rivet  used  is  apt  to  give  trouble.  In- 


FIG.    60— HAKLIDAY'S    APPARATUS. 


so  also  by  leaving  out  the  surrounding  brick.  The 
action  of  this  is  similar  in  most  respects  to  the 
other.  The  fire  gases  instead  of  being  in  two  pipes, 
one  surrounding  the  other,  are  in  numerous  pipes. 
The  flame  as  it  arises  from  the  grate  is  prevented 
from  entering  K,  so  it  goes  through  the  flues  C  to 
a  central  chamber  at  the  back,  from  which  it  is 
drawn  through  pipe  K  to  the  chimney.  The  va- 
pors pass  through  screens  set  in  the  back  plate 
(shown  in  detail  at  Fig.  4)  and  thence  through 
pipe  R.  To  keep  the  screens  clean  a  wire  brush 
e  Fig.  4  is  used  and  worked  from  the  outside  when 
necessary. 


stead  of  there  being  fewer  in  this  apparatus, 
there  se'ems  to  be  need  of  many.  If,  in  the  work- 
ing of  the  apparatus,  these  difficulties  do  not  mani- 
fest themselves,  we  have  in  these  processes,  per- 
haps, one  of  the  best  for  the  destructive  distilla- 
tion of  saw  dust  and  the  like. 

An  apparatus  much  used  in  England  and  Europe 
for  distilling  hardwood  saw  dust  is  the  device  con- 
structed by  Halliday. 

According  to  the  description  of  it  given  by 
Hubbard  in  his  "Distillation  of  Waste  Wood,"  this 
process  is  a  continuous  one,  and  consists  of  a 
cylinder  with  feeding  screw;  according  to  the  speed 


88 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


with  which  the  screw  is  driven,  the  wood  can  be 
exposed  for  a  longer  or  shorter  time  to  the  action 
of  the  heat,  and  thus  a  larger  yield  of  acetic  acid 
is  obtained  than  is  possible  from  the  charcoal 
mounds.  The  fact  is,  however,  not  to  be  ascribed 
to  an  especially  favorable  construction  of  the  ap- 
paratus, but  exclusively  to  the  form  of  the  raw 
material.  From  small  fragments  of  wood,  the  dis- 
tillate is  much  more  rapidly  evolved  than  from 
large  billets,  and  the  distillate  undergoes  much 
less  decomposition  in  th-e  apparatus.  The  saw 
dust  is  thrown  in  the  hopper  B  (Fig.  60). 

In  this  hopper  a  revolving  screw  C  delivers  the 
material  at  an  appropriate  rate  into  a  horizontal 
cylinder.  The  latter  is  heated  by  the  furnace  A. 
A  second  screw  D  keeps  the  material  in  the  retort 
in  constant  motion,  and  at  the  same  time  conveys 


it  gradually  to  the  other  end  of  the  cylinder.  The 
wood  becomes  carbonized  as  it  traverses  the  cylin- 
der so  that  by  the  time  it  reaches  the  further  end 
it  has  parted  with  its  volatile  products.  Two 
tubes  are  connected  with  this  end  of  the  cylinder. 
One  of  these,  F,  descends  into  an  air-tight  closed 
cast-iron  receiver,  or  else  into  a  cistern,  G,  filled 
with  water;  the  other,  E,  carries  off  the  products 
of  distillation  to  the  condenser,  which  consists  of 
tubes  surrounded  with  water.  It  can  be  readily 
seen  that  this  apparatus  with  a  perforated  shaft 
for  steam  could  be  easily  used  for  distilling  pine. 
This  apparatus  has  been  in  use  for  a  long  time. 

In  Viola's  apparatus  an  arrangement  is  made 
to  rotate  the  outer  shell  of  the  retort  in  addition 
to  the  use  of  a  screw  conveyor. 

In   the   illustration   Fig.    61   is   shown   one   form 


FIG.     61— VIOLA     PROCESS. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


89 


of  this  apparatus.  Its  method  of  operation  is  read- 
ily understood  on  account  of  its  similarity  to  the 
Halliday  apparatus  just  described.  The  raw  ma- 
terial enters  at  A,  which  portion  of  apparatus  is 
provided  with  a  stirrer  to  keep  the  material  from 
packing.  As  the  wood  drops  to  chamber  D  it  is 
moved  along  by  the  screw  conveyor  to  the  bottom 
end,  by  which  time  it  should  be  distilled.  The  re- 
tort shell  of  this  part  is  rotated  in  order  to  help 
stir  the  material.  The  vapors  pass  out  through 
B  to  a  suitable  condenser,  while  the  charcoal  is 
drawn  out  from  time  to  time  by  opening  the  cover 
C.  This  apparatus  is  continuous. 

Another  form  is  used  intermittently.     The  feed 
end  is  omitted  and  also  the  screw  conveyor.     One 


fications  can  be  made,  such  as  inclining  the  re- 
tort, extending  the  heads,  changing  the  location 
of  the  rotating  parts,  etc.,  all  of  which  have  been 
considered  in  connection  with  the  process  as  car- 
ried out.  The  illustration  shows  the  form  which 
is  operated  under  slight  pressure,  no  pressure  or 
vacuum,  according  to  the  nature  of  the  substances 
to  be  distilled.  It  can  be  readily  seen  that  such 
an  apparatus  would  be  of  service  in  other  lines  of 
chemical  industry,  where  distillation,  roasting  or 
drying  processes  are  used. 

In  the  distillation  of  wood,  it  could  be  surround- 
ed by  a  brick  furnace  and  saw  dust  and  hogged 
wood  distilled  by  its  means.  Steam  can  be  admit- 
ted to  the  conveyor  shaft  as  well  as  at  the  place 


FIG.     62.— HARPER'S    PROCESS. 


end  is  furnished  with  a  door  for  the  admission  of 
the  wood,  which  is  held  in  position  by  a  frame, 
while  it  is  being  distilled.  The  vapors  escape 
through  B,  as  is  shown.  Charcoal  is  pulled  by 
means  of  the  frames  to  C.  This  opening  is  ar- 
ranged to  dip  under  water  like  in  the  Halliday 
apparatus.  This  process  seems  to  be  very  com- 
plicated and  does  not  appear  to  be  as  efficient 
as  the  Halliday  apparatus,  which  is  far  more  sim- 
ple. 

A  steam  process  continuous  in  action  connected 
with  the  saw  mill  would  be  very  convenient  if  it 
worked  automatically  and  at  the  same  rate  as  the 
saw  dust,  etc.,  was  supplied.  This  suggested  in 
the  year  1900  the  Harper  process,  one  modification 
of  which  is  shown  in.  Fig.  62.  Many  other  modi- 


shown.  In  distilling  rich  wood  an  arrangement  is 
added  which  takes  off  the  resin  formed.  In  dis- 
tilling under  pressure  the  screw  conveyors  are 
so  arranged  that  no  steam  can  blow  through  while 
feeding  and  the  rotating  part  properly  packed. 

The  retort  as  used  in  accordance  with  illustra- 
tion is  filled  partly  full  .by  the  feed  screw  A  and 
the  steam  either  saturated  or  superheated  turned 
in.  The  material  moves  along  the  bottom  of  the 
retort  on  account  of  the  settling  action  of  the 
mass.  The  steam  being  under  low  pressure  can- 
not escape  through  the  conveyor  on  account  of 
the  mass  of  material  in  the  feed  box  and  conveyor 
trough.  A  ready  outlet  for  the  vapors  is  furnished 
at  B,  preferably  screened  to  prevent  saw  dust 
from  blowing  through  the  pipe. 


90 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


The  heads  of  the  retort  are  stationary  and  only 
the  shell  and  the  lifting  vanes  C  rotate.  A  steel 
tire  is  provided  for  the  retort  at  both  ends  so  that 
it  will  stand  the  wear  of  rotating.  No  weight  is 
allowed  on  the  driving  machinery,  the  entire  load 
being  carried  by  the  rolls. 

By  the  time  the  material  reaches  the  rear  end, 
all  the  volatile  matter  is  distilled  and  tbe  vanes 
catching  the  material  lift  it  and  deposit  it  upon 
the  trough  of  the  screw  conveyor  B,  and  thus  it  is 


The  form  of  screw  conveyor  shown  in  these 
forms  of  apparatus  is  not  very  suitable  for  moving 
saw  dust,  but  other  forms  can  be  used  which  are 
suitable.  With  very  fat  wood  the  above  apparatus 
is  supplied  with  a  special  chain  for  scraping  the 
bottom. 

For  destructive  distillation  in  such  a  retort  in- 
stead of  heating  the  shell,  a  self-contained  form 
can  be  used  by  putting  in  flues  similar  to  those 
used  in  the  Larsen  process  or  the  wood  can  be 


FIG.    63— FLEMING'S    PROCESS. 


carried  out  and  dropped  on  to  a  conveyor  leading 
to  the  furnaces. 

At  those  plants  where  turpentine  and  tar  are 
mixed  and  then  separated  one  of  these  retorts 
would  answer  the  purpose.  For  those  who  prefer 
to  distill  the  turpentine  separate  from  the  tar, 
two  would  be  necessary,  one  for  the  turpentine 
and  one  to  destructively  distill  for  the  tar.  As 
used  above,  the  apparatus  would  be  used  for  saw 
dust,  which  would  not  pay  to  distill  destructively, 
so  only  the  turpentine  would  be  taken  off.  In  this 
case  the  shell  should  be  covered  with  suitable  lag- 
ging. 


charred  in  the  retort,  as  illustrated,  by  means  of 
superheated  steam,  thus  requiring  no  brick  fur- 
nace. 

If  required,  this  apparatus  can  be  used  station- 
ary or  intermittently.  In  the  latter  case,  after  the 
retort  was  charged  all  that  would  be  necessary 
would  be  to  stop  the  feed  and  discharge  screws 
until  the  distillation  was  ended. 

By  using  hot  gases  containing  no  oxygen  the  oils 
can  be  extracted  and  the  gases  passed  through  a 
reheater  and  used  over  again.  Gas  takes  up  heat 
and  loses  heat  rather  slowly.  Hardwood  saw  dust 
can  be  distilled  with  this  apparatus. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


91 


All  rotary  and  continuous  processes  are  more 
expensive  to  construct,  cannot  be  worked  well  on 
variable  material,  and  are  difficult  to  make  tight 
under  heavy  pressure.  However,  much  pressure 
is  not  now  used.  They  have  the  advantage  of 
being  made  in  any  length  when  supported  prop- 
erly and  can  thus  be  made  to  hold  100  tons  or 
more,  the  size  being  determined  by  the  rate  of 
distillation. 

The  next  is  Fleming's  process,  shown  in  Fig.  63. 
Not  much  need  be  said  concerning  this  process, 
as  it  is  so  simple  in  construction  that  it  is  ap- 
parent from  the  illustration. 

It  consists  of  a  rotary  retort  working  intermit- 
tently, the  ground  wood  being  fed  in  the  manhole 
10  at  the  top  and  discharged  at  the  bottom  through 
the  same  orifice,  when  the  retort  is  turned. 

To  operate,  steam  is  turned  on  through  the  per- 
forated pipe  shown  and  the  steam  and  turpentine 
vapors  pass  through  the  funnel-shaped  mouth  of 
the  pipe  8  to  the  condenser*  the  retort  being  slowly 
turned  during  the  operation. 

Another  form  of  retort  constructed  on  exactly 
the  same  principles  as  that  above  is  that  of  Coe. 
It  consists  of  a  large  steel  ball,  instead  of  being 
elongated  as  in  Fleming's  process.  The  supports, 
manhead,  steam  and  vapor  pipes,  etc.,  are  adjust- 
ed in  a  similar  manner  to  Fleming's. 

A  sphere  will  stand  pressure  better  than  a  cylin- 
der and  would  be  more  rigid,  but  the  elongated 
form  would  be  heated  to  better  advantage. 

One  feature  noticeable  about  the  process  is 
that  Coe  claims  a  yield  of  25  per  cent  more  by 
his  process  than  by  the  stationary  steam  process, 
and  attributes  it  to  the  stirring  of  the  material 
in  the  retort  and  tbe  breaking  up  of  the  ground 
wood  as  it  rubs  together  while  rotating. 

It  can  be  seen  that  either  of  those  forms  would 
not  cost  much  more  than  a  stationary 'one  and  a 
25  per  cent  extra  yield  would  more  than  pay  the 
initial  cost.  They  must  be  made  thicker  than  the 
others  in  order  to  stand  the  strain  of  suspension 
and  the  weight  of  tbe  wood. 

A  later  process  than  Fleming's  is  that  of  Jack- 
son, Fig.  64.  As  can  be  readily  seen  the  differ- 


ence lies  chiefly  in  turning  the  retort  around  so 
that  it  rotates  from  the  sides  instead  of  the  ends. 
This  makes  it  necessary  to  change  the  arrange- 
ment of  the  steam  pipes  so  as  to  make  them 
longer. 

To  operate,  the  wood  is  dropped  in  at  B,  the 
head  bolted  on  and  steam  turned  in.  The  steam 
supply  enters  the  shaft  at  G,  then  leaves  again  at 


FIG.    64— JACKSON'S    PROCESS. 

C  and  follows  a  pipe  outside  the  retort  and  then 
enters  the  retort  at  J  1.  The  vapors  follow  a  simi- 
lar course,  leaving  the  retort  at  a  point  opposite 
to  J 1  and  coming  back  again  to  the  shaft  at  D 
and  passing  to  a  condenser.  This  arrangement 
of  steam  pipes  and  vapor  pipes  is  entirely  un- 
necessary. There  is  no  reason  why  the  steam 
could  not*  continue  in  the  shaft  until  it  entered 


92 


THE    UTILIZATION    OF    WOOD    WASTE,    BY    DISTILLATION. 


the  retort,  as  in  Fleming's  process,  and  tben  pipe 
to  J 1,  if  necessary. 

A  patent  should  have  been  granted  to  but  one 
of  these  three  parties,  as  the  principle  of  the  one 
is  the  same  as  that  of  the  others. 

A  great  many  patents  have  suggested  the  ad- 
visability of  using  pine  wood  pulp  for  paper-making 
after  the  turpentine  is  extracted. 

The  only  one  ever  tried  is  that  of  Handford's, 
Fig.  65.  A  plant  using  this  process  was  built  near 
a  paper  mill  using  yellow  pine  for  making  pulp 


Al,  where  the  chips  are  torn  into  shreds  by  a 
machine  called  a  fiberizer.  The  material  thus 
treated  falls  upon  the  conveyor  H  by  means  of 
which  it  is  taken  to  the  top  of  the  rotary  digester 
B  and  drops  therein  through  the  manhole  K.  A 
stirrer  with  paddles  is  on  the  inside  of  the  digester 
which  takes  the  material  from  the  entering  end 
K  to  the  opposite  end,  where  underneath  in  a  sim- 
ilar position  to  K  is  another  manhole  which  al- 
lows the  material  to  be  dropped  out  of  the  diges- 
ter. The  steam  enters  and  the  vapors  leave  the 


FIG.    65.— HANDFORD'S    PROCESS. 


by  the  soda  process.  It  proved  unsuccessful  for 
two  reasons  chiefly;  first,  because  in  using  the 
lean  wood  the  operation  of  extracting  the  turpen- 
tine did  not  pay  for  itself,  and  second,  the  residue 
after  treatment  made  a  very  poor  quality  of  pa- 
per. 

As  will  be  found  later,  under  Chapter  XI,  proc- 
esses for  the  preliminary  extracting  of  the  tur- 
pentine from  pine  wood  when  making  paper  pulp 
are  not  necessary. 

Fig.  65  represents  a  plan  of  the  process.  At  A 
is  hog  through  which  the  chunks  of  wood  pass  to 


digester  in  the  same  manner  as  in  Fleming's  proc- 
ess; the  steam  going  in  through  the  shaft  from 
pipe  L  at  one  end  and  going  to  the  condenser 
through  pipe  E  at  the  other  end.  A  closed  con- 
veyor is  under  the  digester  B  and  it  takes  the 
discharged  material  above  DD  and  it  is  permitted 
to  fall  and  pass  through  heavy  steam  heated  rolls, 
which  press  out  the  liquid  material  in  the  resi- 
due; any  vapors  rising  and  entering  pipe  El  and 
thence  going  to  the  condenser.  The  material  that 
is  discharged  from  the  rolls  is  then  used  for  paper 
making. 


THH    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


93 


On  account  of  the  non-success  in  making  paper 
from  the  residue  an  attempt  is  now  being  made 
to  manufacture  straw  board  from  the  pulp.  There 
is  no  use  making  turpentine,  though,  if  the  ap- 
paratus does  not  extract  it  cheaply  enough;  it 
would  be  better  to  make  straw  board  or  pulp  di- 
rect. 

Movable  Retorts. — Under  this  head  come  those 
retorts  that  are  so  made  that  they  can  be  easily 
taken  down  and  transported  from  place  to  place, 
thus  bringing  the  retort  to  the  wood  rather  than 
the  wood  to  the  retort. 

The  first  process  to  be  mentioned  is  that  of 
Dromart,  used  in  France.  Here  retorts'  holding  14 


sote  in  creosoting  lumber,  and  had  a  bearing  more 
on  the  production  of  creosoting  oil  than  on  tur- 
pentine, although  pine  wood  was  used. 

The  illustration  shows  the  process  sufficiently 
to  set  forth  the  idea.  In  Fig.  3,  Fig.  66.  is  repre- 
sented a  retort  set  in  a  furnace  for  heating.  It 
is  divided  into  three  sections,  as  shown  at  e  e,  the 
vapors  escape  by  a,  Fig.  5,  to  a  condenser.  The 
wood  is  taken  in  on  trucks,  as  shown,  and  the 
distillation  proceeded  with  in  the  ordinary  man- 
ner. One  retort  is  used  for  distilling  and  the 
other  for  creosoting. 


FIG.    66.— SMITH'S    PROCESS— Fig.    3. 

cords  are  made  in  sections  each  section  weighing 
about  110  pounds.  This  was  used  way  back  in 
1830.  The  iron  sections  were  made  to  fit  each 
other  so  as  to  make  a  dome  shaped  kiln  and  the 
joints  luted  with  clay.  There  was  a  chimney  at 
the  top  with  arrangements  for  regulating  the 
draft.  The  beat  was  supplied  by  the  carbonizing 
of  the  wood  inside,  as  in  an  ordinary  brick  kiln. 

The  only  other  process  of  the  kind  to  be  dis- 
cussed is  that  of  Smith.  Its  object  was  to  pro- 
vide a  suitable  portable  apparatus  for  distilling 
wood  and  at  the  same  time  be  used  for  creosoting 
lumber.  This  was  devised  at  the  time  that  wood 
creosote  was  used  in  preference  to  coal  tar  creo- 


FIG.    66.— SMITH'S    PROCESS— Fig.    5. 


A  later  process  combining  wood  distilling  and 
creosoting  is  that  of  Davis,  Fig.  67. 

To  operate,  wood  is  placed  on  trucks  on  track 
3  and  the  whole  rolled  into  retort  B  F.  The  re- 
torts are  made  of  brick  or  iron  surrounded  with 
an  envelope  of  brick  or  other  suitable  material, 
tbe  space  between  being  filled  with  sand  so  as 
to  stop  up  any  leaks  that  might  occur  in  the  re- 
torts. Hot  rosin  or  other  preserving  agent  is 
pumped  from  the  heating  vat  6  into  the  retort,  this 
fluid  not  being  hot  enough  to  decompose  the  woody 
fibre,  but  at  the  same  time  being  sufficiently  hot 
to  distill  the  turpentine.  Instead  of  applying  heat 


94 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


to  the  retort,  the  rosin  when  it  becomes  cool  is 
pumped  through  the  heater  24  and  is  reheated,  a 
continuous  circulatory  system  being  kept  up  by 
means  of  pump  20. 

These  retorts  are  preferably  arranged  in  pairs, 
as  shown  and  provided  with  connections  so  ar- 
ranged that  one  retort  may  be  cleaned  and  re- 
charged while  the  other  is  being  operated,  thus 


FIG.    67.— DAVIS'    PROCESS. 

effecting  a  great  saving  in  time  and  obviating  the 
reed  of  repumping  to  and  from  the  main  source 
of  supply  of  the  distilling  and  preserving  fluid. 

The  vapors  from  the  distillation  pass  out  the 
openings  32,  33,  to  the  condenser  36,  where  they 
are  condensed  and  collected. 

There  are  two  processes  devised  by  Weed,  using 
a  bath  of  rosin,  one  for  distilling  terpenes  only 


and  the  other  for  distilling  terpenes  and  also  the 
wood  itself.  The  latest  process  only  is  illustrat- 
ed. Fig.  68  represents  the  arrangement  of  the 
apparatus. 

To  operate,  wood  is  placed  in  the  retort  a  on 
the  netting  g,  situated  above  the  perforated  steam 
pipe  d.  Rosin  is  melted  in  the  boiler  p  and 
pumped  out  by  pump  o  directly  into  the  retort. 
As  it  cools  it  is  drawn  through  pipe  i  to  the 
branch  s,  then  again  to  the  pump  o.  This  time 
it  passes  through  coil  1,  which  is  heated  by  fur- 
nace m  and  then  into  the  retort  through  per- 
forated pipe  j.  As  it  issues  from  these  perfora- 
tions, it  comes  in  contact  with  the  steam  coming 
from  pipe  d  carrying  with  it  the  vapors  of  tur- 
pentine whicb  pass  out  through  c  to  a  condenser. 

When  the  distillation  is  finished,  the  hot  rosin 
is  allowed  to  flow  back  through  valve  z  to  the 
boiler  p,  where  it  is  kept  hot  for  the  next  charge. 
Of  course,  it  could  be  pumped  into  another  retort 
if  desired.  The  wood  is  then  withdrawn. 

In  the  other  form  only  the  retort  is  used.  The 
rosin  and  wood  are  put  into  the  retort  and  a  fire 
started  under  the  bottom  and  the  heat  raised  to 
the  required  point,  the  volatilized  products  pass- 
ing to  a  condenser. 

Neither  form  is  as  good  as  Davis',  although  they 
have  been  used.  ' 

In  the  Craighill  and  Kerr  process,  the  wood  is 
treated  with  a  dilute  solution  of  caustic  soda  in 
order  to  hold  back  the  resins  and  acids,  and  tben 
steamed  in  the  usual  way  at  a  temperature  of  110 
degrees  C.  The  vapors  can  be  passed  through  a 
bone-black  filter  if  desired,  before  condensing.  To 
remove  the  rosin,  etc.,  water  is  added  to  submerge 
the  wood,  steam  is  applied  and  the  wood  is  di- 
gested at  a  temperature  equal  to  the  boiling  point 
of  the  alkaline  solution  with  which  the  mass  was 
saturated  and  the  digestion  continued  until  the 
rosin  has  completely  entered  into  combination  by 
saponification  with  the  alkaline  solution.  There- 
upon the  solution  is  drawn  off  and  the  wood  well 
drained. 

To  make  fibre,  the  wood  is  digested  under  pres- 
sure with  caustic  soda  solution  of  1.075  to  1.10  sp. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


95 


gr.  As  this  solution  attacks  the  fibre  if  the  heat- 
ing is  prolonged,  only  a  portion  of  the  coloring 
matter  is  taken  out  and  the  solution  withdrawn. 
A  solution  of  sodium  carbonate  is  then  added  and 
the  heating  continued  with  or  without  pressure 
until  more  of  the  coloring  matter  is  extracted,  leav- 
ing the  fibre  about  the  color  of  light  manilla  wrap- 
ping paper.  The  fibre  is  then  bleached  by  chlori- 
nated soda. 

This  process  will  need  close  watching  with  vari- 
ous kinds  of  wood  on  account  of  the  different  de- 
grees of  fatness.  The  rosin  can  be  recovered  only 
with  difficulty. 

Hale  &   Kursteiner   don't   use   any   caustic   soda 


thinate  has  been  so  removed  may  be  subjected  to 
destructive  distillation  in  the  ordinary  way  and 
for  ordinary  purposes."  It  is  claimed  all  of  the 
gums,  etc.,  are  eliminated  from  the  wood. 

The  operation  of  the  process  is  simple.  The 
wood  in  blocks  enters  at  A3.  Water  heated  to  130 
degrees  Fah.  by  means  of  steam  coil  B2  is  added, 
and  the  temperature  raised  by  means  of  the  gas 
burner  C  to  about  210  degrees  or  211  degrees  Fah. 
As  the  gums  exude  and  float,  they  overflow 
through  pipe  F  into  the  still  G,  passing  through  a 
glass  observation  bulb  F2  on  the  way.  By  this 
contrivance  it  can  be  seen  whether  any  gum  is 
coming  over  with  the  water.  As  it  is  necessary 


FIG.   68.— WEED'S   PROCESS. 


or  steam  in  their  process,  shown  in  Fig.  69.  This 
invention  is  based  upon  the  discovery  "that  when 
wood  is  subjected  to  the  action  of  a  bath  of  water 
maintained  at  a  temperature  just  below  the  boil- 
ing point  or  approximately  212  degrees  Fah.,  the 
terebinthinate  or  gum  will  separate  from  the  wood 
and  retaining  its  turpentine  or  its  volatile  or 
more  buoyant  constituents  will  rise  to  the  surface 
of  the  bath,  whence  it  may  be  removed  or  caused 
to  flow  over  to  a  suitable  still  in  which  it  may 
be  subjected  to  a  distilling  operation  for  separa- 
tion into  its  constituent  parts,  turpentine,  rosin- 
oil  and  rosin.  The  wood  from  which  the  terebin- 


to  let  water  overflow  with  the  gum,  this  water  is 
drawn  off  through  cocks  1,  2,  3,  4,  5,  wherever  a 
layer  of  it  is  found.  Some  water  is  left  in  the 
still  with  the  gum  and  when  the  still  is  sufficiently 
full  it  is  heated  by  vapor  burner  Gl  to  about  215 
degrees  Fah.,  when  the  turpentine  distills  over 
clear  and  white.  After  the  turpentine  and  water 
are  distilled,  the  rosin  remaining  can  be  distilled 
for  rosin-oil  or  drawn  off  as  rosin. 

Claims  are  made  that  from  128  pounds  of  rich 
long-leaf  straw  pine  wood  during  a  period  of  from 
three  to  five  hours,  one  gallon  of  high-grade  tur- 
pentine and  about  twenty-five  pounds  of  rosin  of 


96 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


fine  quality  are  obtained.  This  is  about  the  same 
yield  as  from  other  processes. 

Unfortunately,  others  who  have  tried  the  same 
process  several  years  ago,  using  very  rich  pine 
coming  from  a  yellow  pine  saw  mill,  do  not  seem 
to  be  able  to  get  any  satisfactory  results.  This 
shows  that  the  process  requires  too  much  skill  in 
order  that  the  ordinary  operator  might  succeed. 

It  is  possible  that  in  some  cases  that  an  extrac- 
tive process  might  prove  of  service  under  some 
conditions,  particularly  when  working  with  very 
fat  wood.  To  supply  this  possible  want  the  author 
has  devised  an  apparatus  which  consists  in  chip- 
ping the  wood  to  the  size  required  for  paper  stock 
or  the  like  and  then  bringing  it  into  a  chamber 
in  a  continuous  manner,  where  it  is  acted  upon 
by  a  suitable  solvent,  such  as  ether,  carbon  bi- 
sulphide, carbon  tetra  chloride,  alcohol,  etc.,  this 


solvent  being  continually  reused  and  kept  in  circu- 
lation in  a  suitable  manner;  the  extracted  matter 
being  removed  from  time  to  time  and  the  solvent 
evaporated  and  condensed.  The  fibre  left  is  white 
and  soft.  The  residue  left  after  evaporating  the 
solvent  is  distilled  with  steam,  which  removes  the 
turpentine,  the  rosin  remaining  in  the  still  from 
whence  it  can  be  withdrawn  hot.  The  color  of 
the  rosin  depends  upon  the  color  and  age  of  the 
wood,  dead  wood  giving  a  light  red,  which  can 
be  bleached,  if  necessary. 

Conveyor  Processes. — Under  this  head  will  be 
described  those  processes  which  use  conveyors  of 
some  kind  to  make  the  wood  pass  through  a  heated 
zone.  The  first  of  these  was  probably  Kalliday's, 
which  has  been  mentioned  under  rotary  retorts. 
Another  retort  said  to  be  better  than  Halliday's 
is  that  of  Bowers.  In  this  process  a  long  rectangu- 


U 


FIG.   69.— HALE  &  KURSTEINER  PROCESS. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


97 


lar  box,  not  over  a  foot  or  two  high,  is  divided 
into  parallel  segments  by  means  of  partitions.  At 
the  end  of  each  partition  is  set  a  pulley  or  sprock- 
et wheel  on  a  vertical  axis.  A  continuous  chain 
conveyor  works  in  and  out  of  each  partition.  Ar- 
rangements are  made  for  tightening  the  chain, 
when  necessary,  while  the  distillation  is  in  prog- 
ress. To  make  a  bend  in  the  conveyor,  the  flights 
of  the  chain  are  hung  from  the  side  of  the  chain 
and  thus  pass  under  the  sprocket  wheel  while  the 
sprockets  engage  the  chain  above  the  flights. 

The  sawdust  enters  at  one  end  of  the  apparatus 
and  as  it  winds  back  and  forth  in  advance  of  the 
conveyor  flights  it  is  completely  distilled.  The 


same  apparatus,  when  gently  heated,  is  used  as  a 
dryer.  It  is  said  that  much  success  is  encountered 
using  these  retorts  for  distilling  hardwood  chips, 
a  brick  furnace  being  used  for  heating  purposes. 
Generally  two  are  used;  one  for  drying  and  the 
other  for  distilling.  Such  a  system  might  be  of 
service  in  distilling  fat  pine;  the  first  retort  tak- 
ing off  the  turp  and  the  second  one  the  tar. 

The  next  patent,  that  of  Dobson,  agitated  the 
lumber  trade  for  a  while.  It  is  a  very  slight  mod- 
ification of  a  Russian  process,  which  never  ma- 
terialized. The  type  is  so  distinctly  different  from 
the  others  that  were  exploited  at  the  time  that  it 
is  interesting  to  know  wherein  its  usefulness  lies. 


FIG.    70.— DOBSON'S    PROCESS. 


98 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


It  is  a  definite  project  to  advance  ground-up  wood 
by  means  of  suitable  conveyors,  directly  through 
a  brick  furnace,  and  while  passing  through  the 
cooler  parts  of  the  furnace,  the  wood  is  to  be 
pressed  and  steamed,  thus  expressing  the  tar  and 
distilling  the  turpentine;  the  residual  wood  to  be 
used  for  paper  making. 

In  the  illustration,  Fig.  70,  a  brick  furnace  is 
shown  at  Fig.  3  with  grates  on  both  sides,  4.  The 
conveyor  space  is  shown  at  3  and  is  arranged  so 
that  the  furnace  gases  are  excluded. 

The  operation  of  the  process  would  be  simple 
enough  if  it  would  work  at  all,  but  the  inventor 
fails  to  make  any  arrangement  for  the  collection 
of  the  turpentine  vapors.  The  material  passes 


In  the  Kerr  process  is  a  device  which  ought  to 
work  well,  provided  the  form  of  screw  conveyor 
shown  is  suitable  for  moving  chipped  wood.  The 
illustration,  Fig.  71,  shows  the  arrangement  very 
clearly. 

The  ground  wood  enters  the  hopper  5  and  falls 
upon  the  screw  conveyor  4.  Steam  enters  through 
the  shaft  by  means  of  port  holes  6,  the  vapors 
from  the  wood  passing  through  9,  9,  9,  etc.,  to  a 
condenser.  With  high  pressure,  the  steam  would 
also  blow  out  through  the  hopper,  so  only  light 
pressure  steam  should  be  used. 

When  the  wood  gets  to  the  end  of  this  conveyor, 
it  drops  down  13  to  another  conveyor,  which*  does 
not  fit  the  trough  so  closely  as  the  first.  Here 


^^,/spiryipi  .rjCffl- 

\T/zi^lW7it/iYyifTyif\y/iv7[i  i 


FIG.  71.— KERR'S  PROCESS. 


through  the  furnace  on  the  conveyor,  where  it  is 
heated  sufficiently  to  draw  the  resin,  steam  being 
added  to  facilitate  the  operation  (turpentine  would 
escape  and  an  outlet  to  a  condenser  should  bave 
been  made).  When  the  material  reaches  the  rear 
end  of  the  furnace  it  is  passed  through  a  series 
of  squeezing  rolls,  9,  10,  11,  Fig.  1,  and  thence  out 
at  the  rear  end.  Such  an  operation  could  never 
work  with  sawdust,  as  was  intended,  as  there  is 
scarcely  any  resin  in  it,  and  only  under  careful 
operating  with  fat  pine.  By  heating  the  hogged 
wood  without  using  live  steam,  it  might  be  pos- 
sible to  sufficiently  melt  the  rosin  so  that  most  of 
it  could  be  squeezed  out.  It  would  seem,  though, 
that  some  turpentine  must  be  lost  unless  some 
provision  were  made  for  collecting  it. 


the  wood  is  treated  with  the  alkaline  solution 
mentioned  in  Craighill  and  Kerr's  process,  the 
level  being  kept  by  means  of  the  overflow  pipe  16. 
Steam  is  admitted  to  the  trough  in  a  similar  man- 
ner as  it  is  in  the  first  one,  but  for  the  purpose 
only  of  keeping  the  alkaline  solution  hot. 

This  form  of  continuous  process  is  very  effective 
for  the  removal  of  turpentine.  One  trouble  would 
be  that  the  chips  would  blow  through  pipe  9  into 
the  condenser  pipe.  This  could  be  prevented  by 
using  screens.  Another  trouble  is  the  expense  of 
the  construction.  A  screw  conveyor  4  inches  in 
diameter  will  deliver  100  bushels  (equal  to  118 
cubic  feet  approximately)  in  one  hour.  The  usual 
time  of  distillation  with  sawdust,  as  ordinarily 
practiced,  is  one  hour  for  each  particle  of  wood. 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


99 


With  a  4-inch-  conveyor  with  a  distilling  period 
of  one  hour  the  trough  should  be  large  enough  to 
hold  a  cord  of  wood  in  order  that  all  the  wood 
passing  through  might  be  acted  upon  for  one  hour. 
This  would  require  a  trough  over  1,500  feet  long. 
With  a  screw  3  feet  in  diameter,  the  trough  would 
have  to  be  nearly  20  feet  in  length*.  It  would  be 
better  to  use  a  rotary  retort  with  a  small  con- 
veyor at  each  end.  But  with  a  distilling  period 
of  only  15  minutes  or  less,  then  the  trough  would 
be  made  much  smaller  and  this  apparatus  would 
be  very  efficient. 

An  apparatus  working  on  the  same  principle  has 
been  in  use  in  another  industry  for  some  time. 
Instead  of  using  one  long  conveyor  several  are 
placed  one  under  the  other  and  the  whole  encased 
with  a  suitable  covering. 

There  are  several  patents  based  on  this  same 
principle,  each  with  a  screw  conveyor  in  a  closed 
trough,  some  using  steam  and  some  hot  gases.  It 
is  difficult  to  distinguish  any  material  difference 
in  most  of  them. 

The  Heidenstam  process  is  a  device  by  means 
of  which  an  attempt  is  made  to  briquette  sawdust 
and  then  distill  the  briquettes  to  make  charcoal 

and  by-products  from  the  wood  contained  therein. 

i 

Very  elaborate  plants  have  been  designed  for 
carrying  out  this  process,  but  it  is  doubtful  if  any 
of  them  will  pay,  and  it  is  certain  that  they  will 
not  in  this  country,  where  charcoal,  the  only  prod- 
uct now  of  much  value  that  is  produced  by  this 
method,  can  be  cheaply  obtained.  Formerly  the 
production  of  wood  alcohol  by  this  method  might 
have  made  the  process  useful  in  the  hardwood  re- 
gion, but  now  that  the  tax  has  been  removed  from 
grain  alcohol,  this  feature  is  lost.  The  process  is 
very  ingenious  and  has  one  point  that  is  very  im- 
portant, and  that  is  the  pressing  of  the  briquettes 
while  distilling. 

.  The  great  objection  to  the  process  is  the  diffi- 
culty in  compressing  sawdust.  Many  attempts  have 
been  made  to  do  this  by  engineers  so  as  to  make 
a  more  compact  fuel,  but  they  have  all  signally 
failed  unless  a  very  expensive  and  uneconomical 
binding  agent  is  used.  By  the  above  method  a 


very  poor  briquette  is  formed,  and  it  is  only  by 
the  action  of  a  poor  compressing  apparatus  in  the 
retort  that  any  hard  charcoal  briquettes  are  formed 
at  all,  and  these  only  few  in  number  as  compared 
with  the  total  carbonized. 

For  pine  wood  this  process  is  scarcely  suitable, 
for  it  is  easier  to  take  the  turpentine  out  before 
briquetting  and  thus  the  only  good  briquetting 
would  do  would  be  to  make  the  sawdust  or  ground- 
wood  suitable  for  charcoal  when  sawdust  is  used, 
or  charcoal  and  tar  when  fat  wood  is  used.  Char- 
coal and  tar  can  be  made  from  fat  wood,  if  nec- 
essary, without  first  hogging  it,  and  to  treat  saw- 
dust in  this  manner  simply  for  charcoal  could  not 
possibly  pay.  The  by-products  from  pine  wood, 
such  as  wood  alcohol  and  acetic  acid,  are  not  of 
sufficient  importance  to  count  on,  and  at  most 
works,  when  incidentally  produced,  are  not  saved. 

If  it  should  be  advisable  to  make  charcoal  from 
sawdust  or  hogged  wood,  which  might  possibly 
be  the  case  when  located  near  a  blast  furnace,  it 
would  be  better  to  carbonize  in  a  rotary  retort, 
such  as  one  of  those  described,  which  could  be 
done  in  one-fourth  the  time  needed  when  the  wood 
is  in  solid  form,  and  tnen  briquette  the  charcoal, 
using  the  tar  formed  as  a  binding  agent.  With 
sawdust  the  tar  formed  would  be  of  such  poor 
quality  that  this  would  be  a  good  way  of  utiliz- 
ing it. 

A  method  of  distilling  by  superheated  steam  has 
lately  come  into  use  in  Sweden.  Although  the  use 
of  superheated  steam  for  charring  wood  has  long 
been  known,  hardwood  distillers  did  not  use  it 
much,  because  it  diluted  the  acid  liquors  too  much. 
It  has  the  further  disadvantage  of  requiring  large 
condensers  and  stronger  retorts. 

A  series  of  retorts  are  used,  each  holding  200 
to  1,000  cu.  ft.  The  hottest  steam  is  introduced 
into  the  one  most  nearly  charred  and  the  coolest 
steam  into  the  one  just  charged.  Ten  retorts  are 
used  in  a  series  and  carbonization  is  completed  in 
12  to  20  hours  and  drawing  and  charging  in  four 
to  five  hours,  so  that  each  retort  can  be  worked 
off  in  24  hours.  The  greater  part  of  the  heat  is 
required  for  evaporating  the  moisture  contained 


100 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


in  the  wood,  but  cooler  steam  can  be  used  for  this 
purpose  and  hotter  steam  for  charring.  The  steam 
together  with  the  gases  evolved  from  the  wood 
pass  from  one  retort  to  the  next,  and  so  on.  When 
carbonization  is  completed  in  one  retort  saturated 
steam  is  passed  in  for  one  hour  and  this  becomes 
superheated  to  some  extent  and  after  passing 
through  the  superheater  is  used  for  completing 
the  charring  of  the  next  retort.  After  the  steam, 
water  is  introduced  into  the  retort  in  small  quan- 
tities and  afterwards  for  one  hour  a  fine  spray  of 
water  is  showered  upon  the  charcoal,  which-  is 
then  ready  to  be  drawn. 

The  heavy  oils  are  condensed  •  and  fall  into  a 
covered  tank  containing  boiling  water.  The  steam 
and  gases  from  the  finished  retort  are  led  through 
this  tank  and  serve  to  heat  the  water  where  the 
heavy  oils  are  condensed.  These  oils  have  a  boil- 
ing point  of  200  to  250  degrees  C.,  and  by  using 
superheated  steam  the  yield  is  said  to  be  increased 
17  per  cent  and  the  oil  to  be  of  much  better  qual- 
ity. In  the  further  description  of  this  process, 
the  wonderful  statement  is  found  that  only  15  per 
cent  of  the  weight  of  the  charcoal  produced  is 
needed  for  fuel. 

To  avoid  diluting  the  distillate  with  water  when 
superheated  steam  is  used  for  carbonizing,  Was- 
bein  used  hot  gases  direct  from  a  gas  producer  to 
distill  the  wood.  The  charcoal  produced  is  used 
in  the  gas  producer.  This  requires  careful  ma- 
nipulation and  large  condensers,  as  not  only  the 
distilled  products  from  the  wood,  but  also  the  hot 
gases  must  be  cooled.  Processes  of  this  kind  are 
used  in  Germany. 

Pierce  Process. — In  this  process  as  described  by 
Landreth  Proc.  A.  A.  A.  S'.,  1888,  the  charring  of 
the  wood  is  effected  in  circular,  flat-top,  brick  kilns 
holding  50  cords  each.  The  wood  is  charred  by 
heat  produced  by  gas  burned  in  a  brick  furnace 
under  the  kiln,  and  into  and  through  which  the 
products  of  combustion  pass.  The  gaseous  prod- 
ucts of  the  dry  distillation  of  the  wood  pass  from 
the  kiln  to  the  condensers,  where  the  tarry  and 
liquid  products  are  condensed  and  the  gas  sent 
back  to  the  kiln.  Thus,  none  of  the  charcoal  pro- 


duced is  burned  to  carbonize  other  wood,  as  in  the 
common  pits  or  ovens.  The  gas  which  elsewhere 
is  wasted  is  here  not  only  sufficient  to  effect  the 
carbonization  of  the  wood,  but  furnishes  fuel  for 
the  boilers  required  about  the  works. 

In  another  description  of  the  process  it  is  stat- 
ed that  there  is  a  large  amount  of  gas  left  over. 
The  gas  burned  under  the  furnace  passes  through 
the  red-hot  charcoal  in  the  kiln,  thus  causing  the 
carbon  dioxide  to  be  reduced  to  the  monoxide  at 
the  expense  of  the  charcoal. 

Such  a  process,  although  largely  used  in  dis- 
tilling hardwood,  cannot  be  very  well  applied  to 
pine  wood.  The  gas  produced  by  pine  wood  dis- 
tillation is  not  sufficient  to  effect  carbonization, 
besides  pine  wood  should  never  be  heated  to  such 
a.  degree  that  carbon  dioxide  would  be  reduced 
to  carbon  monoxide. 

Although  all  these  processes  that  have  been  de- 
scribed relate  chiefly  to  pine  wood,  yet  all  the  de- 
structive distillation  processes  could  be  applied  to 
hardwood  by  simply  omitting  the  part  that  re- 
lates to  the  turpentine.  Instead  of  working  up 
the  oils,  the  pyroligneous  acid  is  saved  and  wood 
alcohol  and  acetates  made  in  customary  manner. 
A  description  of  a  German  process  for  carbonizing 
pine  will  be  given  later,  wbich  utilizes  the 
acid  in  this  way.  All  the  pyroligneous  acid  that 
is  made  by  distilling  pine  by  the  foregoing  proc- 
esses can  be  treated  in  this  manner.  The  yield 
is  so  small,  however,  that  it  hardly  pays. 

The  patents  herein  described  are  given  below 
in  the  order  of  their  application. 

Wheeler,    7-5-1870  Krugr.  10-1-1903 

Messau,  7-3-1872  Matthieu,   10-12-1903 

Stanley,    1872  Palmer,  12-9-1903 
Hansen  &  Smith,  10-10-1885    Dobson,   12-23-1903 

Berry,    12-15-1885  Mallonee,    12-23-1903 

Wheeler,    8-26-1886  Hoskins,  2-1-1904 

E.    Koch,    3-1-1887  Broughton,    6-13-1904 

Smith,    12-13-1887  Fiveash,    6-24-1904 

A.    Koch,    8-13-1889  Davis,    7-16-1904 
Koch  &  Danner,  8-26-1889        Harper,  7-22-1904 

Badgley,  4-8-1890  Fleming,   7-28-1904 

Inderleid,   7-1-1892  Hirsch,    8-1-1904 

Spurrier,   9-10-1898  Palmer,  8-20-1904 

Spurrier,  10-11-1898  Ross  &  Edwards,  11-11-1904 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION.  101 


Larsen,   10-7-1899  Handford,    12-27-1904  Viola,    1-28-1903  Kerr,    9-28-1905 

Weed,    1-6-1900  Copilovich,   1-12-1905  Palmer,    5-11-1903  Craighill   &   Kerr,    10-3-1905 

Weed,    2-15-1901  Williams,    1-16-1905  Bilfinger    &    Halleck,  Jackson,    10-11-1905 

Roake,     6-21-1901  Gardner,   3-11-1905                                    4-25-1903  Davis,    10-23-1905 

Gilmer,    6-25-1901  Sibbett  &  McLean,  6-20-1905  Clark  &  Harris,  6-10-1903        Snyder,    12-1-1905 

Adams,  12-27-1901  Jewett,   6-29-1905  Bilflnger,   7-11-1903  McMillan,    3-24-1906 

Chapman,    3-17-1902  James  &  James,  7-6-1905  Mallonee,   7-18-1903  Craighill  &   Kerr,    4-17-1906 

Viola,   1-15-1903  F^iis,    9-28-1905  Douglas,  9-1-1903  Hale  &  Kursteiner,  8-14-1906 


CHAPTER  VII. 

THE  EXECUTION  OF  THE  PROCESSES  OF  WOOD  DISTILLATION. 


A  description  of  each  individual  process  cannot 
be  given  in  detail  here,  but  one  of  each  general 
kind  can  be  given  as  a  type.  In  distilling  it  is  . 
absolutely  necessary  to  work  for  certain  definite 
products  so  as  to  obtain  large  yields  of  tbese. 
"When  working  for  large  quantities  of  turpentine 
more  time  needs  to  be  taken  and  the  heat  kept 
low  so  as  not  to  draw  out  tar.  In  the  same  way 
when  working  for  large  quantities  of  tar  the  dis- 
tillation must  take  place  slowly  or  large  quantities 
of  gas  will  be  found  at  the  expense  of  the  tar 
and  charcoal. 

The  Steam  Process. — In  this  process  it  will  be 
considered  that  a  series  of  vertical  retorts  are  to 
be  used  set  in  a  row.  Above  each  retort  should  be 
a  bin,  unless  each  retort  is  worked  alternately.  Un- 
derneath the  retorts  should  be  troughs  of  sufficient 
size  to  hold  the  residue  dropped  from  the  retorts. 
In  this  trough  should  run  a  conveyor  to  the  boil- 
ers, or  elsewhere.  Above  the  bins  and  retorts 
should  be  a  conveyor  from  which  the  ground  wood 
from  the  hog  drops  by  means  of  suitable  chutes 
to  the  bin  or  retort. 

To  start  the  plant  the  first  retort  should  be 
filled  with  wood  and  steam  turned  in  until  the 
pressure  reaches  not  over  5  or  10  pounds,  or 
such  pressure  as  is  determined  upon.  At  first  it 
is  advisable  to  allow  the  steam  to  rush  in  rather 
rapidly  in  order  to  quickly  heat  the  retort.  The 
stirrers  should  be  started  and  the  distillation  con- 
tinued until  all  the  oil  has  been  distilled  over,  or 
rather  until  only  such  a  small  quantity  is  pres- 
ent in  the  distillate  as  to  no  longer  pay  to  con- 
tinue. The  steam  as  it  warms  the  retort  soon 
finds  its  way  to  the  condenser,  and  there  with  the 
oil  is  condensed  and  flows  out  to  the  receiver. 
The  proportion  of  oil  and  water  varies  with  the 
richness  of  the  wood,  most  of  the  oil  coming 
over  in  the  first  part  of  the  operation. 


This  oil  is  not  pure,  but  consists  of  oil  and  resin- 
ous matters,  with  a  small  proportion  of  ethers, 
aldehydes  and  ketones,  which  gives  it  a  decided 
odor.  Oil  is  only  slightly  soluble  in  water,  and 
it  is  only  necessary  to  allow  the  mixture  coming 
from  the  condenser  to  settle  when  the  water  goes 
to  the  bottom.  By  using  two  or  three  tanks  the 
oil  from  the  first  one,  containing  water  in  sus- 
pension, overflows  into  the  second  one,  where  more 
water  separates,  and  from  thence  to  the  third,  by 
which  time  enough  water  is  taken  out  to  furnish  an 
oil  suitable  for  simple  redistilling  in  order  to 
make  it  ready  for  the  market. 

It  is  claimed  by  some  that  in  distilling  saw- 
dust only  the  gum  turpentine  found  in  the  sap  is 
distilled  by  the  steam,  but  such  is  not  the  case, 
for  not  only  is  the  gum  oil  distilled,  but  also  that 
contained  in  the  heart  wood.  In  addition  to  this, 
resin  comes  over  mechanically,  thus  coloring  the 
crude  product,  but  not  giving  it  the  bad  odor  that 
would  come  if  the  tar  was  started. 

In  the'  meantime,  the  other  retorts  are  filled 
and  started,  and  the  material  still  coming  in  the 
conveyor  is  allowed  to  fall  into  the  first  bin.  In 
the  case  of  sawdust  the  first  retort  would  prob- 
ably be  distilled  by  the  time  the  other  retorts 
were  filled,  and  the  bin  would  not  be  necessary. 
However,  if  the  first  retort  is  not  finished,  the 
material  should  be  collected  in  the  bin  and  the 
bin  fitted  with  a  large  opening  at  the  bottom  to 
allow  the  material  to  drop  out  quickly  into  the 
retort  when  required.  The  charge  being  worked 
off,  the  steam  valve  is  closed,  the  bolts  taken  off 
the  door  at  the  bottom  is  opened,  and  the  residual 
material  allowed  to  drop  out.  The  door  is  again 
fastened  on  and  a  new  charge  dropped  in  from  the 
bin  above.  The  residue  is  conveyed  to  the  boiler. 

A  modified  working  of  the  process  is  to  use  sim- 
ply two  retorts,  or  steamers,  and  have  them  of  a 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


103 


size  sufficient  to  handle  all  the  raw  material.  By 
filling  one  while  the  other  is  distilling  the  use  of 
bins  is  not  necessary.  It  can  be  seen,  though, 
that  this  means  two  retorts  against  a  bin  and  a 
retort,  and,  as  a  bin  ought  to  be  the  cheaper,  this 
modification  means  greater  initial  cost  for  retort. 
In  addition,  with  two  retorts  each  would  have  to 
have  special  valves  and  connecting  pipes,  which 
further  increases  the  initial  cost.  The  gain  would 
be  in  the  saving  of  time  in  dropping  the  distilled 
material  out  and  filling  the  retort  from  the  bin, 
a  process  which  ought  not  to  take  much  time. 
Even  if  stirrers  could  be  used  satisfactorily,  it  will 
be  found  that  the  sawdust  will  pack  and  scaffold, 
or  arch,  thus  making  sawdust  expensive  to  distill 
and  to  discharge. 

It  will  be  seen  that  the  execution  of  the  steam 
process  is  not  a  very  difficult  matter,  and  all  that 
it  needs  in  the  way  of  labor  is  a  man  of  sufficient 
intelligence  to  take  care  of  a  boiler  when  a  hog 
is  not  used  and  an  ordinary  stationary  engineer 
when  a  hog  and  engine  are  used.  Of  course,  on 
a  large  scale  where  considerable  product  is  made, 
good  superintendence  is  necessary  in  order  to  ob- 
tain the  most  economical  workings. 

Steam  and  Destructive  Distillation. — In  this  proc- 
ess we  have  a  more  difficult  proposition  than  in 
the  plain  steam  process.  Neither  this  process  nor 
the  one  to  follow  have  any  especial  advantage,  un- 
less charcoal  is  to  be  made,  consequently  the  proc- 
ess should  be  made  to  yield  as  much  turpentine  in 
the  first  stages  and  as  much  tar  and  charcoal  in 
the  later  stages  as  possible,  and  but  little  gas. 
Although  the  gas  formed  has  a  high  heating  value, 
it  takes  more  fuel  to  make  it  and  at  the  same  time 
the  yield  of  the  more  valuable  by-products  of  the 
wood  is  less,  particularly  of  charcoal. 

This  is  the  process  the  writer  would  recommend 
when  the  three  primary  products,  turpentine,  tar 
and  charcoal,  are  wanted,  but  for  turpentine  and 
tar  without  charcoal  a  special  process,  to  be  de- 
scribed later,  seems  to  be  the  more  suitable. 

In  the  preparation  of  the  wood  a  general  idea 
must  be  obtained  from  experiment  as  to  the  yield 
in  turpentine  from  a  cord  of  four-foot  wood,  two- 


foot  wood  and  one-foot  wood  in  fifteen  hours'  heat- 
ing.     From    this    data    can    be    obtained    the    in- 
creased value,  if  any,  that  is  occasioned  by  saw- 
ing  the   wood   into   short   pieces.     The  wood   pre- 
pared in  the  proper  manner  is  then  charged  into 
the   retort,   either  by  means  of  cars  or  by  hand, 
and   the   doors   fastened,   gauges,   etc.,   adjusted,   a 
fire  started  in  the  furnace,  and  the  heat  raised  as 
quickly   as   possible   to   212   degrees   Fah.,   without 
injuring   the   brickwork    and    retort    seams.      This 
takes  from   one  to  three  hours,  according  to  the 
size  of  the  retort,  then  superheated  steam  is  al- 
lowed to  enter  the  retort  in  considerable  quantity 
until  the  contents  thereof  are  brought  to  approxi- 
mately   325    degrees    Fah.,    when    the    supply    of 
steam  should  be  cut  down  so  that  a  considerable 
portion  of  the  condensed  matter  is  oil,  say  not  less 
than  one-twenty-fourth.     The  heat  is  maintained  at 
325  degrees  Fah.,  not  because  the  oil  will  not  dis- 
till at  a  temperature  less  than  this,  but  because 
it  is  necessary  for  the  heat  to  penetrate  to  the 
inside  of  the  block  of  wood  and  thus  draw  out  all 
the  oil  and  resin.     Care  must  be  taken  not  to  go 
above   this  temperature  or  the  wood  would  begin 
to  decompose  and  empyreumatic  vapors  come  over. 
Cellulose  begins  to  decompose  at  320  degrees  Fah., 
but  only   slightly.     Wood   is   a   poor  conductor   of 
heat,  and  it  is  not  definitely  known  how  large  a 
block    may   be,    and    at   the    same   time    be    small 
enough  to  allow  the  heat  to  draw  the  resin  from 
the   middle   of   the   block   when   the   outside    tem- 
perature  is  325   degrees   Fah.,  nor  is  it,  definitely 
known   how   long   it   would   take    for   the   heat   to 
penetrate    to    the    middle    when    the    temperature 
outside  is  held  at  that  degree.     There  is  no  rea- 
son  why  this  cannot  be  determined,  and  it  prob- 
ably will  be   soon. 

The  amount  of  distillate  which  comes  over  by 
this  treatment  need  not  be  large,  but  should  be 
a  very  decided  quantity.  It  is  better,  though,  to 
use  furnace  heat  as  much  as  possible,  so  as  to 
have  the  furnace  hot,  ready  for  the  second  part 
of  the  operation,  so  only  enough  steam  should  be 
used  to  carry  over  the  vapors.  This  saves  con- 
densing water,  also.  When  the  condenser  hasn't 


104 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


been  used  for  some  time,  a  green  colored  oil  is 
obtained  at  first,  due  to  the  dissolving  by  the  oil 
of  the  copper  acetate  left  in  the  pipe  from  a  pre- 
vious distillation.  Often  the  oil  is  water-white  at 
first,  quickly  changing  to  yellow,  and  then  to  am- 
ber as  more  and  more  resin  is  distilled.  When 
the  amount  of  oil  falls  off  and  the  temperature 
in  the  retort  still  remains  the  same,  it  is  an  indi- 
cation that  most  of  the  light  oils  have  been  dis- 
tilled, and  that  to  obtain  heavier  oil  with  a  higher 
boiling  point  the  heat  must  be  increased.  The 
appearance  of  gas  about  the  fifteenth  hour  after 
starting  when  the  retort  has  been  gradually  heat- 
ed indicates  a  changing  point.  The  oils  coming 
over  can  be  tested  with  a  hydrometer,  if  desired, 
but  with  proper  firing  the  receiver  should  be 
changed  and  any  gas  apparatus  coupled  up  if  not 
already  in  position.  Steam  can  now  be  left  on  or 
closed  off,  according  to  the  notion  of  the  operator. 
The  author  prefers  to  use  steam  throughout  the  en- 
tire operation,  even  when  an  exhauster  is  used,  as 
a  certain  effect  is  produced  that  might  not  be  other- 
wise. As  no  acetic  acid  is  usually  recovered,  the 
excess  of  water  in  the  distillate  is  not  much  to  be 
feared,  unless  the  proportion  is  such  that  the  tar 
and  acid  will  not  properly  separate. 

From  now  on  the  progress  of  the  distillation 
can  be  determined  in  various  ways  by  experienced 
men.  The  heating  should  not  be  great  enough  to 
cause  back  pressure  from  the  gas,  and  at  the 
same  time  a  steady  stream  should  flow  from  the 
end  of  the  condenser  with  weak  force.  The  gases 
formed  are  at  first  blue  when  ignited,  from  the 
combustion  of  the  carbon  monoxide,  and  as  the 
distillation  proceeds  this  flame  becomes  gradual- 
ly yellow,  and  toward  the  end  of  the  distillation 
the  heavy  white  yellow  flame  of  the  heavy  hydro- 
carbons makes  its  appearance  and  continues  un- 
til the  distillation  is  finished. 

Of  course,  the  distillation  can  still  be  carried 
on  by  means  of  an  ordinary  thermometer  until  the 
last  stages  are  reached,  when  it  is  necessary  to 
use  a  pyrometer  of  some  kind,  or  a  special  1000 
degree  Fah.  mercurial  thermometer.  When  the 
temperature  reaches  500  and  in  some  cases  600 


degrees  Fah.,  some  operators  change  the  receiver 
again  and  then  continue  the  distillation  to  obtain 
the   thicker   tar.     Others   collect   the   entire   tarry 
distillate   in   one  vessel   and   then   redistill.     Ordi- 
nary distillation  would  be  finished  when  the  tem- 
perature reached  a  few  degrees  over  800  degrees 
Fah.,  but  in  some  cases,  owing  to  the  formation 
of  paraffins  of  high  boiling  points   it  is  better  to 
run  to   about  900   degrees   Fah.     The   author   has 
sometimes   been   obliged   to   go   even   higher   than 
that.     With    separate   condensers   for   each    retort 
the  end  point  is  readily  ascertained  by  the  slack- 
ing off  in  the  quantity  of  the  distillate.    When  this 
point  is  reached   the  fires  can  be  withdrawn   and 
the  gas   turned   into   another  fireplace.     The   heat 
of  the  furnace  walls  will  be  found  to  be  sufficient 
to   complete   the   distillation.     By   having   the   fur- 
naces hot  at  the  time  the  wood  is  ready  to  decom- 
pose the  destructive  distillation  itself  requires  but 
eight  hours  in  a  three-cord  retort.     If  lined  with 
brick    the    retort    will    not    be    specially      injured. 
When  the  distillation  is  ended  the  retort  will  be 
found  to  be  red  hot  on  the  bottom.     It  is  allowed 
to   cool   until   the   iron   becomes   black,   when   the 
charcoal  is  drawn.     The  residual  gas  remaining  in 
the  retort  should  be  touched  off  like  when  making 
coal   gas,   and   the   admittance   of   gas   from   other 
retorts    prevented.     The   heads   are   then   removed 
and   the   charcoal   immediately   withdrawn.     Using 
cars,  the  products  can  be  easily  pulled  into  cool- 
ers without  much  loss  from  burning.     Others  sim- 
ply draw  the  charcoal  into  a  pit  and  wet  it  with 
water  or  cover  it  with  wet  charcoal  dust.     Some 
drop  the  charcoal  into  cars  and  lute  on  a  sheet- 
iron  cover. 

Destructive  Distillation. — This  process  is  carried 
on  exactly  the  same  as  the  foregoing  in  the  latter 
part  of  the  operation  and  very  similarly  in  the 
first  part,  except  no  steam  is  used,  consequently 
the  first  distillates  are  smaller  and  darker.  The 
first  portion  is  usually  caught  in  separate  re- 
ceivers, but  this  is  not  always  the  case. 

A  rather  complete  plant  for  the  utilization  of 
pine  wood  as  carried  out  in  Germany  is  shown  in 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


105 


Fig.   72.     This   is   a  plan   of  a  plant  for   distilling 
ten  cords  of  pine  wood  in  twenty-four  hours. 

The  wood  is  brought  in  on  cars  on  the  track  A 
fitted  with  suitable  turntables,  B,  B,  B,  B.  To  use 
the  labor  employed  properly  the  retorts  are  charged 
one  after  the  other,  instead  of  all  at  once.  The 
retorts  (c,  c,  etc.)  on  the  left  would  be  charged 
first,  and  those  on  the  right  last.  The  distilla- 
tion proceeds  in  the  usual  manner,  the  vapor  be- 
ing condensed  in  the  condensers  D,  D,  etc.,  two 
pipes  being  in  one  cooling  box.  The  distillates 
from  all  the  retorts  go  down  pipe  E  to  the  tank 
F,  F,  F,  where  the  oil  and  acid  separate.  The 
oil  goes  to  the  tank  G,  and  the  acid  containing 
the  wood  alcohol  is  either  sent  to  one  of  the  stills 
J,  J,  or  to  the  tank  H  to  be  first  neutralized  with 
lime.  In  making  brown  acetate  the  lime  is  added 
to  the  liquor  in  H  and  the  excess  of  lime  and 
sediment  removed  by  the  filter  press  I.  The  liquor 
is  then  transferred  to  an  iron  still  J  and  the  alco- 
hol distilled.  To  make  grey  acetate  several  meth- 
ods are  employed.  In  one  the  acid  and  alcohol  are 
distilled  in  the  copper  still  J,  leaving  the  tar  as 
a  residue.  This  tar  is  forced  in  a  spray  under 
the  boilers  and  used  for  fuel  unless  the  market 
price  warrants  its  sale.  The  alcohol  and  acid  are 


then  brought  to  the  neutralizing  tank  H,  where 
the  liquor  is  exactly  neutralized  with  lime  and 
filter-pressed.  The  alcohol  is  then  removed  by 
distillation  in  the  iron  still  J  and  collected  at  K. 
Another  method  is  to  distill  the  crude  pyroligenous 
acid  and  collect  the  alcohol  until  the  sp.  gr.  of 
the  distillates  is  1  and  then  to  change  the  re- 
ceiver and  collect  acetic  acid  separately.  This 
acid  is  then  neutralized  and  evaporated.  Another 
method  is  to  distill  the  pyroligneous  acid  in  a  cop- 
per still  and  to  make  the  vapors  pass  through 


p« 

|c 

. 

A 
i 

C; 

r  *"-) 

ej 

-^*- 

-*k_ 

C 

c 

—  JJ- 

jo 

!c 

i 
c 

-*  — 

ci 

1 

-J£- 

B      A 


B 


B 


B 


M 


O 


FIG.  72— GERMAN  DESTRUCTIVE  DISTILLATION  PLANT. 


106 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


milk  of  lime,  which  absorbs  the  acetic  acid  and 
permits  the  alcohol  to  pass  on  to  the  condenser. 
This  latter  method  would  take  less  fuel,  as  the 
acetate  liquor  would  be  hot.  It  would  be  difficult 
to  regulate  the  supply  of  lime  for  neutralizing. 

In  the  North  a  method  is  used  whereby  the 
lime  is  added  directly  into  the  iron  still  from  a 
lime  box  situated  above  it.  The  still  is  furnished 
with  a  stirrer  to  thoroughly  mix  4h«  Hqtrhi,  other- 
wise the  pyroligneous  acid  is  treated  by  the  first 
method  both  for  grey  and  brown  acetate  of  lime. 

The  acetate  or  neutralized  liquor  thus  produced 
is  evaporated  to  a  thick  paste  in  the  steam-jack- 
eted pans,  L,  L,  furnished  with  stirrers.  This 
paste  is  then  spread  out  on  the  acetate  pans,  M, 
to  dry,  care,  being  taken  not  to  char.  At  some 
plants  the  drying  takes  place  in  rooms  heated 
with  waste  furnace  or  retort  gases.  (See  Calcium 
Acetate,  Chapter  X.)  With  this  particular  process 
the  acetate  pans  are  located  in  the  boiler  room, 
where  the  water  pump  N  is  also  situated. 

The  alcohol  coming  from  the  still  J  is  collected 
until  the  gravity  is  about  1.  This  weak  alcohol 
is  then  sent  to  the  still  O  and  distilled.  In  this 
still  alcohol  of  .965  sp.  gr.  is  converted  into  por- 
tions, some  as  light  as  .816  sp.  gr.,  containing  95 
per  cent  alcohol.  The  general  average  of  this  still 
is  considered  to  be  82  per  cent.  Care  must  be 
taken  not  to  let  the  wood  oil  mix  with  the  high 
proof  alcohol  or  it  will  render  it  non-miscible  with 
water.  This  is  usually  avoided  by  collecting  the 
different  portions  separately  and  returning  some 
of  the  liquor  to  be  redistilled.  With  the  German 
method  the  first  runnings  consisting  of  more  or 
less  colored  liquor  is  caught  separately  until  the 
middle  fraction  begins  to  distill  over.  After  the 
middle  portion  distills,  products  with  a  higher 
boiling  point  come  over,  their  presence  being  first 
noticeable  by  the  turbidity  of  the  distillate  pro- 
duced when  water  is  added  to  it.  Subsequently 
the  distillate  itself  is  rendered  turbid  and  eventual- 
ly it  comes  over  in  two  layers,  oil  and  water. 
Finally  only  water  comes  over,  impregnated  with 
empyreumatic  substances.  The  alcohol  rendered 
turbid  by  water  can  be  treated  in  two  ways;  it 


can  be  added  to  the  turbid  distillate  and  the  mix- 
ture added  to  the  next  charge  of  crude  in  the 
same  still,  or  it  can  be  diluted  until  it  shows  a 
specific  gravity  of  0.934  and  allowed  to  rest  for  a 
few  days,  when  the  greater  portion  of  the  hydro- 
carbons separate  as  an  oily  layer  on  the  top,  and 
can  be  drawn  off.  The  alcoholic  fluid  left  is  re- 
distilled over  time  and  makes  strong  alcohol  that 
does  not  become  turbid  upon  the  addition  of 
water.  The  oily  fractions  are  mixed  together  and 
redistilled  separately,  when  a  further  quantity  of 
middle  fraction  is  obtained.  The  wood  oil  ob- 
tained is  known  as  red  oil,  and  is  usually  burnt. 
By  distilling  the  strong  alcohol  obtained  from  the 
above  still  after  adding  a  little  sulphuric  acid  in 
the  still  P  a  very  strong  highly  refined  alcohol 
is  produced. 

At  some  plants  the  crude  wood  alcohol  is  passed 
through  towers  containing  wood  charcoal,  which 
serves  to  remove  some  of  the  ketones,  aldehydes 
and  tarry  matters. 

None  of  these  processes  serve  to  remove  ace- 
tone. To  do  this  several  methods  are  used;  one 
is  to  form  a  compound  of  wood  alcohol  and  cal- 
cium chloride,  which  is  stable  at  100  degrees  C. 
By  gently  heating  the  acetone  is  driven  off,  and 
then  by  adding  water  and  raising  the  temperature 
to  100  degrees  C.  the  calcium  chloride  compound 
decomposes  and  the  methyl  alcohol  distills.  Oth- 
ers add  caustic  potash  and  iodine  until  the  yellow 
color  disappears,  then  distill.  (Regnault  &  Ville- 
jean.)  The  watery  alcohol  is  repeatedly  rectified 
over  lime,  and  finally  over  sodium  or  phosphoric 
anhydride  to  remove  the  last  traces  of  water. 

The  crude  turpentine  oil  containing  the  tar,  re- 
sin, etc.,  is  taken  to  the  tank  G,  from  whence  it 
enters  still  R,  where  the  light  oils  are  removed 
and  are  collected  in  tank  S.  From  S  the  oil  goes 
to  the  washer  T,  where  it  is  washed  with  alkali 
water,  acid,  and  again  with  water,  and  then  recti- 
fied in  the  fractionating  still  U,  and  is  then  settled 
ready  for  shipment.  The  tar  is  removed  from  the 
still  R  and  is  immediately  ready  for  shipment. 
The  residues  from  the  other  stills  are  mixed  with 
crude  oil  and  again  distilled  until  they  begin  to 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


107 


accumulate,  when  they  are  otherwise  disposed  of. 
The  charcoal  left  in  the  retort  is  taken  out  by 
means  of  a  chain  fastened  to  a  scraper,  placed  in 
the  rear  of  the  retort,  and  dropped  into  an  iron 
bogie  running  on  the  small  track.  The  bogie  is 
covered  with  sheet  iron  and  the  edges  luted  with 
'  clay  to  exclude  air  and  the  whole  rolled  away  to 
cool  in  a  storehouse.  It  is .  necessary  to  have  one 
car  for  each  retort,  and  about  three  for  bringing 
in  the  wood. 

Special  Process. — The  use  of  a  rotary  retort 
should  be  described  here,  as  the  author  believes 
that  this  method  will  eventually  be  the  one  used 
to  utilize  all  kinds  of  waste  wood,  particularly  the 
average  dead  pine  found  in  the  woods.  Wherever 
such  pine  can  be  found  yielding  four  gallons  of 
turpentine  to  the  cord  and  not  costing  over  $1.50 
per  cord,  delivered,  this  process  can  be  success- 
fully employed.  Under  such  disadvantageous  con- 
ditions the  closest  economy  in  working  is  neces- 
sary. 

The  combination  of  apparatus  suggested  would 
be  two  rotary  retorts,  a  boiler,  a  superheater,  a 
blower,  an  exhauster,  two  condensers,  two  stills 
and  condensers,  one  water  pump  and  a  hog.  Those 
who  prefer  mixing  the  distillates  need  have  but 
one  retort  and  condenser  and  extra  still.  A  con- 
veyor from  the  hog  to  the  retort  would  be  needed 
and  one  from  the  end  of  the  retort  to  the  boiler. 
The  wood  should  be  hogged  in  the  usual  manner 
and  brought  to  the  retort  for  distillation.  In  the 
first  retort  the  turpentine  should  be  worked  off 
and  condensed  and  the  chips  discharged  into  the 
second  retort,  where  they  are  thoroughly  charred 
by  means  of  superheated  steam,  hot  inert  gases, 
or  by  means  of  fire  gases  passing  through  special 
flues  or  through  the  wood  itself. 

With  fat  wood  each  operation  should  be  per- 
formed in  six  hours  and  the  charred  wood  used 
for  fuel  in  addition  to  whatever  other  fuel  is 
needed.  The  tar  carried  over  by  the  steam  is 
condensed  in  the  usual  manner,  and  then  redis- 
tilled to  recover  any  light  oils,  and  by  passing  a 
current  of  superheated  steam  through  the  mass 
while  hot  sufficient  of  the  heavier  oils  can  be 


carried  over  and  the  tar  left  of  the  proper  con- 
sistency. By  this  method  of  operating  the  tar 
obtained  would  be  of  sufficient  value  to  pay  for 
tire  fuel  and  wood,  and  the  turpentine  to  pay  for 
the  .labor  and  leave  a  small  profit  in  addition. 
Charcoal  is  of  no  value  In  ^«ost  communities  ex- 
cept in  small  quantities,  so  this  method  -would 
probably  be  the  best  that  could  be  devised  to 
treat  the  average  wood  found  in  any  locality.  It 
offers  further  attractiveness  in  that  when  the  sup- 
ply of  wood  is  exhausted  the  entire  outfit  could 
be  easily  removed  to  another  .place.  For  those 
who  prefer  to  use  but  one  retort  it  is  best  to 
have  it  long  so  that  the  end  farthest  from  the 
feed  can  be  heated  to  the  charring  point,  and  the 
hot  gases  led  out  through  a  pipe  at  the  feed  end, 
the  heat  from  these  gases  thus  being  utilized  to 
partially  distill  the  incoming  wood  with  which 
they  come  in  contact  on  the  passage  through  the 
retort.  The  products  can  then  be  refined.  In  all 
cases  it  is  better  to  coat  the  shells  of  the  retort 
with  asbestos,  or  other  covering,  so  as  to  pre- 
vent radiation  as  much  as  possible.  , 

In  those  cases  where  very  poor  wood  is  used 
it  might  be  that  the  tar  made  became  too  dark, 
owing  to  the  lack  of  resin.  This  might  be  mixed 
with  the  fine  charcoal  and  briquetted  and  sent  to 
an  iron  furnace,  or  again  distilled  to  form  spe- 
cial charcoal  bricks  such  as  are  used  in  foot-warm- 
ers. It  can  be  readily  understood  that  in  these 
cases  only  a  small  plant  could  pay,  as  the  de- 
mand for  charcoal  in  the  latter  form  would  be 
limited,  indeed.  With  blast  furnaces  the  results 
would  be  more  encouraging  and  a  large  plant 
would  be  needed.  This  would  be  an  easy  way  of 
solving  the  problem  in  such  districts.  It  is  claimed 
by  manufacturers  of  briquette  machinery  that  bri- 
quetting  can  be  done  for  50  cents  per  ton.  By  the 
ordinary  method  of  distilling  large  wood  it  takes 
from  twelve  to  twenty-four  hours  to  char,  whereas 
by  this  method  only  six  hours  is  necessary,  so  this 
difference  in  time  would  more  than  pay  for  the 
cost  of  briquetting. 

Wood  Gas  Making. — So  far  it  has  only  been  in- 
timated that  wood  gas  is  yielded  in  the  destructive 


108 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


distillation  of  wood  in  sufficient  quantities  to  pay 
for  working  for  gas  alone.  However,  the  yield  of 
gas  ranges  from  20  to  50  per  cent  of  the  weight 
of  the  wood.  By  ordinary  distillation  20  to  30 
per  cent  is  the  usual  yield,  but  by  rapid  heating 
the  yield  is  greatly  increased.  The  weight  of  1,000 
cubic  feet  of  wood  gas  is  about  50  pounds  at  62 
degrees  Fah.,  so  a  ton  of  sawdust  might,  under 
certain  conditions,  be  made  to  yield  1,000  pounds 
of  gas,  or  about  20,000  cubic  feet,  whereas  one  ton 
of  the  best  gas  coal  from  Grahamite,  W.  Va.,  gives 
but  15,000  cubic  feet  of  coal  gas  and  most  coals 
only  about  10,000  to  12,000.  Wood  gas  must  be 
purified  with  lime  to  remove  the  carbon  dioxide, 
and  then  it  has  an  illuminating  value,  according 
to  Liebig,  of  6  to  5  compared  with  coal  gas.  (See 
analysis  of  wood  gas  under  Chapter  XII.) 

To  carry  out  the  process  of  making  gas,  several 
methods  are  used.  One  consists  in  heating  the 
wood  in  ordinary  retorts  and  then  passing  the  va- 
pors through  a  superheater,  which  decomposes 
them  and  forms  uncondensable  gases.  One  meth- 
od is  to  throw  the  wood  as  quickly  as  possible 
into  a  glowing  retort  and  to  collect  the  gases  in 
the  ordinary  manner.  Another  utilizes  the  princi- 
ples of  a  water  gas  apparatus,  and  treats  the  wood 
in  a  similar  manner.  Another  method  is  to  col- 
lect the  gas  separately,  then  by  using  the  char- 
coal in  a  water  gas  system  the  charcoal  can  be 
glowed  by  the  air  blast  and  the  wood  gas  passed 
through  it  to  decompose  as  far  as  possible  the 
carbon  dioxide  contained  therein,  then  steam  added 
until  the  temperature  became  too  low  for  decom- 
position. If  the  charcoal  was  too  expensive,  coal 
or  coke  could  be  used.  Then  the  distilling  method 
with  hot  gases,  or  preferably  producer-gas,  could 
be  used. 

An  attempt  will  not  be  made  to  enter  into  the 
details  of  operation  of  these  various  methods,  as 
wood  gas  manufacture  is  not  apt  to  be  a  nourish- 
ing industry,  owing  to  the  fact  that  the  proper 
place  to  make  wood  gas  economically  would  be 
in  the  woods,  because  wood  is  too  bulky,  as  com- 
pared with  coal,  for  transport;  and  it  is  not  to 
be  expected  that  it  would  pay  to  transport  the 


gas  even  by  pipe  line,  except  in  those  cases  where 
the  gas  could  be  made  near  the  city. 

The  author  would  suggest  the  possibility,  how- 
ever, of  utilizing  sawdust  for  gas  making  in  those 
States  where  lumber  mills  are  located  in  com- 
paratively large  cities.  To  do  this  it  would  be 
necessary  to  use  those  forms  of  apparatus  spoken 
of  for  distilling  sawdust  destructively.  Of  these, 
Larsen's  and  Harper's  rotary  retorts,  Halliday's 
screw  retort,  and  Bower's  chain  retorts  might  be 
used.  The  last  two  are  usually  enclosed  in  brick 
so  no  further  modification  would  be  necessary. 
With  pine  or  fir  distillation  the  turpentine  could 
be  taken  off  in  a  previous  operation  and  the  resi- 
due destructively  distilled  for  gas.  Larger  vapor 
pipes  and  condensers  would  be  necessary,  owing 
to  the  sudden  formation  of  gas  when  the  wood  is 
brought  in  contact  with  the  hot  retort.  In  all 
cases  it  is  presupposed  that  the  wood  has  been 
dried.  To  use  the  gas  under  a  pressure  of  1-12  to 
%  inch  of  water,  bat  wing  tips  having  a  width  of 
about  0.0394  incb  give  the  best  results.  A  "Wels- 
bach  mantle  is  also  very  serviceable. 

A  method  used  in  France  endeavors  to  utilize 
wood  in  generators  that  are  designed  to  supply 
gas  for  motors.  The  consumption  of  ordinary 
wood  for  such  purpose  is  about  five  pounds  per 
horsepower  hour.  The  heating  is  done  from  top 
to  bottom.  The  wood  that  first  enters  is  charred 
and  falls  to  the  bottom  as  red-hot  charcoal.  The 
air  blast  having  been  heated  by  the  pipe  through 
which  the  gas  is  escaping,  enters  the  top  of  the 
generator  and,  coming  in  contact  with  fresh  wood, 
partially  distills  it,  and  the  products  of  distilla- 
tion pass  through  the  red-hot  charcoal  at  the  bot- 
tom, thus  decomposing  the  tar  to  form  more  gas 
and  the  combined  vapors  and  gases  pass  out  at 
a  pipe  at  the  bottom  through  a  filter  and  then  to 
a  separator.  It  can  be  seen  that  unless  carefully 
regulated  the  supply  of  oxygen  in  the  air  would 
be  exhausted  before  reaching  the  charcoal  at  the 
bottom  of  the  generator  and  the  charcoal  remain 
unburned.  Arrangement  is  made  for  drawing  this 
residual  charcoal  into  water,  where  the  ashes  will 
sink  and  the  charcoal  float.  This  charcoal  could 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


109 


be  dried  and  returned  to  the  top  of  the  apparatus. 

Wood  gas  has  some  advantages  over  coal  gas 
when  used  in  gas  engines.  For  this  reason  at- 
tempts may  be  made  to  utilize  wood  waste  by 
converting  it  into  gas. 

Any  of  the  processes  herein  described  that  are 
based  on  destructive  distillation  are  suitable  for 
making  gas.  Those  that  arrange  to  protect  the 
retort  from  the  effects  of  severe  heating  and  those 
that  treat  small  pieces  of  wood  effectively  are  to 
be  preferred. 


Two  forms  of  gas  generators  can  be  formed  from 
these  classes  of  apparatus;  one  using  closed  re- 
torts and  the  other  being  open  for  the  admission 
of  air  similar  to  a  gas  producer.  As  a  gas  pro- 
ducer the  apparatus  would  necessarily  be  of  the 
suction  type,  although  in  a  few  instances  the  type 
using  a  blast  could  be  employed. 

Those  familiar  with  coal  gas  generators  can 
readily  add  the  necessary  modification  to  wood  dis- 
tilling apparatus  to  bring  satisfactory  results. 


CHAPTER  VIII. 

REFINING  PROCESSES. 


General  methods  of  refining  have  already  been 
given  and  some  special  methods  of  refining  have 
been  given  under  the  different  processes.  The  pat- 
ents now  to  be  described  are  considered  chiefly  be- 
cause they  show  a  definite  method  of  carrying  out 
principles  already  in  use  or  known,  rather  than 
because  they  relate  to  any  new  methods  or  prin- 
ciples. 

Crude  turpentine  as  it  comes  from  the  retort 
is  invariably  more  or  less  colored  at  some  stage 
of  the  operation,  no  matter  what  the  process  is 
that  may  be  used,  consequently  refining  is  neces- 
sary to  remove  objectionable  impurities.  This 
latter  is  especially  true  where  all  the  products 
of  distillation  are  mixed  together  and  then  re- 
fined. 

In  all   methods  of     refining     the   same   general 


object  is  to  be  attained.  The  crude  turpentine 
may  contain  light  and  heavy  oils  and  tar.  The 
object  of  refining  then  is  to  separate  the  turpen- 
tine from  these  other  ingredients  when  they  are 
present.  Light  oils  in  most  processes  are  pro- 
duced from  the  rosin  by  local  action,  while  in 
some  destructive  distillation  processes  the  pres- 
ence of  light  oils  is  always  to  be  expected.  In  the 
steam  process,  the  objectionable  impurity  is  a 
heavy  oil  and  is  easily  separated  by  ordinary  dis- 
tillation, the  light  oil  coming  first  and  the  heavy  oil 
remaining  in  the  still  or  collected  separately. 

Chemicals  are  often  used,  such  as  lime  and 
caustic  soda  and  even  acid;  the  use  of  mineral 
acid  is  not  to  be  commended  as  it  bas  a  tendency 
to  change  pinene  into  dipentene.  All  these  chem- 
icals have  been  in  use  for  a  long  time,  coupled 
with  steam  distillation. 

By  noticing  the  methods  described  under  the 
following  patents,  a  general  idea  can  be  obtained 
of  the  methods  used  in  refining  the  crude  turpen- 
tine. 

Mallonee's  Apparatus — The  method  is  shown  in 
Fig.  73.  It  consists  of  a  series  of  similar  units, 
working  separately  in  a  similar  manner.  The 


j    "-^g 


FIG.    73— MALLONEE'S   PROCESS. 


THE,    UTILIZATION    OP    WOOD    WASTE    BY    DISTILLATION. 


Ill 


operation  of  the  stills  shown,  have  been  described 
in  part  under  Mallonee's  process,  Fig.  37.  The 
distillate  from  the  retort  is  caught  in  three  sep- 
arate fractions  according  to  the  specific  gravity; 
the  first  fraction  being  caught  from  0.855  sp.  gr. 
to  0.920;  the  second  fraction  from  0.92  to  0.96 
sp.  gr.,  and  the  third  fraction  from  0.96  sp.  gr.  to 
the  end  of  the  distillation.  The  refining  apparatus 
shown  in  Fig.  73  deals  entirely  with  the  first  two 
fractions  and  the  operation  is  carried  on  in  a  sim- 
ilar manner  with  both  fractions,  the  only  differ- 
ence being  in  the  proportion  of  the  different  prod- 
ucts which  distill  over. 

The  crude  oil  is  placed  in  still  1  and  heated  in 
the  ordinary  manner  by  means  of  steam  (see  Fig. 
17,  Steam  Still).  The  light  oil  vapors  pass  up 
pipe  8,  which  is  about  twenty  feet  in  length,  and 
are  condensed  in  the  tubular  condenser  9  and  pass 
into  the  receiver  23.  To  prevent  the  turpentine 
vapors  passing  to  the  condenser  with  the  light 
oil,  a  spray  of  water  is  applied  at  10  to  cool  the 
vapor  pipe,  the  water  passing  down  the  pipe  to 
the  pan  12,  from  whence  it  is  carried  away.  A 
gas  trap  is  shown  at  22  and  an  oil  and  water  sep- 
arator and  receiver  at  23. 

After  distilling  the  light  oils,  the  remaining  oil 
in  the  still  is  allowed  to  flow  into  still  2  through 
pipe  27.  In  this  still  the  turpentine  is  distilled 


in  the  usual  manner  by  means  of  steam.  The 
distilled  turpentine  is  separated  from  the  water 
at  33  and  allowed  to  flow  into  still  4,  where  it  is 
redistilled  in  order  to  make  it  clear.  The  residue 
in  stills  2  and  4  is  permitted  to  flow  into  still  3 
by  means  of  pipes  40  and  37,  respectively.  From 
this  still  heavy  oils  are  recovered  by  distilla- 
tion with-  steam,  as  before,  and  collected  in  two 
fractions  in  the  separator  46.  This  separator  is 
divided  into  two  compartments  and  the  first  frac- 
tion of  the  distillate,  comprising  oils  lighter  than 
water,  passes  from  the  pipe  44  into  the  compart- 
ment 49,  and  the  second  fraction,  consisting  of 
oils  heavier  than  water,  is  collected  in  compart- 
ment 50.  The  water  is  separated  by  gravity  from 
the  oils  and  the  oils  sent  to  storage  tanks  or  bar- 
relled. 

Gilmer's  Refining  Process — The  crude  material 
used  in  this  apparatus  is  the  oil  obtained  by  dis- 
tilling pine  wood  at  a  low  temperature,  and  is  only 
impregnated  to  a  slight  extent  with  creosote  or 
tar  vapors. 

A  combination  of  the  apparatus  used  is  shown  in 
Fig.  74.  At  1  is  a  receiving  tank  for  the  crude 
oil  and  acid  water  coming  from  the  retort.  The 
acid  water  being  drawn  off,  the  crude  oil  is  al- 
lowed to  flow  into  still  5,  where  it  is  mixed  with 
about  50  per  cent  of  pure  water.  The  mixture  is 


FIG.    74— GILMER'S    REFINING    PROCESS. 


112 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


heated  by  means  of  the  steam  coil  7,  which  is 
kept  under  the  water  so  as  not  to  be  in  contact 
with  the  oil.  The  distilled  oil  and  water  are 
condensed  in  the  tubular  condenser  13  and  are 
collected  in  the  tank  20.  The  residue  in  the  still 
5  is  thick  tar  and  is  sold  as  such.  The  mixture 
in  tank  15  settles  by  gravity  and  the  water  is 
drawn  off.  The  oil  is  then  treated  with  lime  water 
of  about  3  or  4  degrees  Baume,  in  the  proportion 
of  one  part  of  lime  water  to  two  of  turpentine. 
The  mixture  is  then  subjected  to  a  thorough 
agitation  and  aeration  by  blowing  air  there- 
through for  about  one  hour.  The  mixture  is  again 
allowed  to  settle  and  decanted  to  separate  the 
lime  water.  The  turpentine  is  then  again  distilled 
in  still  19  in  a  similar  manner  as  before.  To 
avoid  injuring  the  product  the  distillation  is  per- 
formed slowly,  about  four  barrels  being  distilled 
in  eight  hours.  The  steam  in  the  close  coil 
should  be  at  a  temperature  of  about  335  degrees 
Fah.  The  vapors  from  the  second  distillation  are 
condensed  by  means  of  the  tubular  condenser  25 
and  are  collected  in  a  storage  tank  28. 

Heber's  Process — The  two  processes  just  given 
require  a  specially  prepared  crude  product.  In 
the  Heber  process  the  idea  is  to  purify  the  bad- 
smelling  oils  produced  by  destructive  distillation 
processes  by  a  chemical  treatment  consisting  of 
treatment  with  oxidizing  compounds.  The  process 
requires  considerable  care,  as  turpentine  is  also 
affected  by  the  chemicals  used,  and  an  excess  must 
therefore  be  avoided.  Before  starting  the  process 
the  oil  should  first  be  removed  from  the  bulk  of 
the  tar  by  ordinary  distillation  with  steam.  This 
crude  oil  containing  tarry  impurities  is  then  dis- 
tilled over  lime  to  remove  the  remainder  of  the 
tar.  A  mixture  of  one  to  two  per  cent  of  lime 


\vitb  water  is  used  and  the  distillation  carried  on 
by  means  of  steam.  The  oil  still  contains  some 
coloring  and  odoriferous  matter.  To  the  oil  is 
added  a  sufficient  quantity  of  a  ten  per  cent  soap 
solution  to  thoroughly  dissolve  or  emulsify  the 
oil,  the  whole  being  mixed  in  a  still  provided  with 
a  suitable  agitator.  When  emulsified,  a  five  per 
cent  solution  of  permanganate  solution  holding 
from  three  to  five  pounds  of  potassium  perman- 
ganate and  four  to  six  pounds  of  sulphuric  acid  of 
66  degrees  Baume  in  solution  is  slowly  added, 
the  mixture  being  constantly  agitated  or  stirred. 
This  agitation  is  continued  until  the  permanganate 
solution  introduced  into  the  still  has  completely 
lost  its  color,  after  whicb  by  the  addition  of  cal- 
cium chloride  or  zinc  sulphate,  the  soap  solution 
is  precipitated  as  insoluble  calcium  or  zinc  soap. 
The  turpentine  is  then  distilled  in  the  usual  man- 
ner by  the  use  of  steam. 

The  oxidizing  of  the  soap  emulsion  can  be  ac- 
complished by  using  chromic  acid  and  sulphuric 
acid  in  the  same  strength  and  proportions  as  are 
used  with  the  permanganate  solution.  When -salts 
of  chromium  are  used,  about  six  to  nine  pounds  of 
potassium  bichromate  (or  an  equivalent  quantity  of 
sodium  bichromate)  should  be  used  for  each  one 
hundred  pounds  of  oil  which  has  been  treated  with 
soap  solution.  These  six  to  nine  pounds  of 
bichromate  are  converted  into  a  five  per  cent 
aqueous  solution  and  four  to  seven  pounds  of 
concentrated  sulphuric  acid  of  66  degrees  Baume 
slowly  added  to  the  same.  The  treatment  is  car- 
ried on  further  as  with  permanganate. 

It  can  be  easily  understood  that  if  the  quantity 
of  impurities  present  varied  much,  there  would 
be  danger  of  losing  turpentine  in  considerable 
quantity. 


CHAPTER  IX. 

GENERAL  CONSIDERATIONS  FOR  THE  ESTABLISHMENT  OF  A  PLANT. 


To  those  contemplating  the  erection  of  a  plant 
for  wood  distillation  the  several"  conditions  and 
requirements  herein  contained  are  essential  to  suc- 
cess, and  in  special  cases  other  considerations 
•would  be  necessary. 

The  first  essential  is  a  supply  of  raw  material 
of  the  proper  quality.  There  must  not  be  any 
guess-work  about  this,  but  the  amount  and  the 
quality  of  the  material  should  be  definitely  known 
in  order  to  regulate  the  size  of  the  apparatus. 
It  is  best  to  own  the  necessary  raw  material,  but 
if  not  owned  it  is  not  best  to  buy  a  lot  of  wood 
until  the  success  of  the  plant  is  assured.  On  the 
other  hand,  owners  of  raw  material  will  be  found 
to  quickly  raise  the  price  unless  some  provision  is 
made  in  advance  for  a  sufficient  supply.  For  this 
reason,  it  is  better  in  such  cases  to  obtain  an  op- 
tion at  a  definite  price  for  a  certain  period. 

To  estimate  the  quantity  of  material  to  be  found 
a  simple  riding  over  the  land  will  not  suffice. 
The  wood  should  be  gathered  from  a  certain  tract, 
cut  up  and  separated  into  the  various  qualities, 
and  these  separate  portions  tested  for  the  amount 
of  oil.  Having  determined  this,  further  calcula- 
tions can  be  made  as  to  the  expected  success  of 
the  venture.  Manufacturers  of  machines  claim 
anything  from  a  yield  of  five  gallons  for  sawdust 
to  fifty  gallons  for  fat  wood.  Generally  these 
tests,  if  made  at  all,  are  made  upon  one  stick,  or 
one  lot  of  wood,  and  are  not  safe  estimates. 

After  having  satisfactorily  determined  tb^ 
amount  of  raw  material,  the  next  point  to  be 
considered  is  its  location.  Some  of  the  best  wood 
for  distillation  is  located  in  such  inaccessible 
places  that  it  is  not  to  be  considered  at  all,  while, 
on  the  other  hand,  inferior  wood  can  be  obtained 
so  much  more  cheaply  that  it  would  pay  better 
to  use  it.  If  possible,  it  is  best  to  have  the  supply 
where  it  can  be  reached  by  both  rail  and  water. 
The  water  route  would  be  cheaper,  both  for  trans- 


porting and  loading,  but  it  has  the  disadvantage 
in  that  the  wood  near  the  bank  has  generally 
been  culled  for  steamboat  purposes  and  is  conse- 
quently inferior.  With  railroad  transportation,  the 
loading  is  more  expensive,  although  somewhat 
compensated  for  in  the  unloading.  With  tram 
roads  the  wood  is  also  apt  to  be  culled.  One  ad- 
vantage in  this  previous  gathering  of  the  wood 
is  the  fact  that  laborers  can  be  more  readily  ob- 
tained who^  are  used  to  that  sort  of  work,  and 
probably  have  teams  ready  and  can  haul  by  con- 
tract, thus  saving  one  of  the  greatest  troubles  in 
the  business.  A  difference  of  50  cents  per  cord 
in  the  cost  of  raw  material  will  often  ruin  the 
prospects  of  a  plant. 

Another  important  feature  is  the  location  of  the 
plant  itself.  A  steam  plant  requiring  but  few  re- 
pairs and  not  occupying  much  space,  nor  employ- 
ing much  labor,  might  be  placed  directly  in  the 
woods  itself,  other  conditions  not  being  consid- 
ered. With  a  destructive  distillation  plant,  where 
the  retorts  are  often  out  of  order,  close  proximity 
to  a  repair  shop  would  seem  advisable.  However, 
the  difficulty  of  obtaining  a  few  laborers  to  live 
in  the  woods  and  stay  would  seem  to  indicate  that 
the  proper  location  of  a  plant  should  be  sufficient- 
ly near  a  town  of  some  size  so  that  in  an  emer- 
gency laborers  could  be  obtained  more  easily.  An- 
other point  to  be  considered  in  point  of  location 
is  the  disposition  of  the  product.  In  this  industry, 
wagon-hauling  won't  do  like  the  custom  in  many 
instances  practiced  in  making  gum  spirits;  the 
plant  must  be  located  on  a  railroad,  and,  if  pos- 
sible, connected  with  some  water  route.  This  is 
particularly  true  with  those  plants  making  tar 
and  charcoal,  both  of  which  are  bulky  articles  as 
compared  with  their  intrinsic  value.  Of  course,  a 
junction  of  two  opposing  railroads,  coupled  with 
water  communication,  would  be  an  ideal  combina- 
tion seldom  realized.  Furthermore,  in  making 


114 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


charcoal  a  market  for  the  same  must  be  found 
near  at  hand. 

After  deciding  upon  the  location,  the  treatment 
of  the  wood  before  distillation  should  be  consid- 
ered. Wood  for  this  industry  should  be  bought  by 
weigbt,  dry,  and  the  diameter  limited  to  6  inches. 
This  is  especially  true  when  using  knots,  as  one 
cannot  tell  what  the  yield  will  be  by  the  cord,  as 
wood  is  of  different  lengths  and  sizes  and  is  gen- 
erally very  crooked;  also,  the  fatter  the  wood 
the  heavier  it  is,  and  thus  more  inducement  is  of- 
fered to  gatherers  to  supply  the  rich  wood  in  pref- 
erence. After  the  wood  is  delivered,  further  treat- 
ment is  generally  necessary.  In  the  case  of  steam 
distillation  yielding  turpentine  only,  the  finer  the 
material  is  hogged  the  better  will  be  the  results. 
The  exact  degree  of  fineness  that  would  be  the 
most  economical  can  be  determined  by  experience, 
and  would  be  dependent  upon  the  difference  in 
yield  in  a  given  time  as  compared  to  the  cost  of 
labor  and  time  expended  to  comminute  it. 

With  the  destructive  process  it  is  an  open  ques- 
tion whether  it  is  better  to  use  the  wood  long  or 
to  saw  it  into  short  lengths. 

The  loss  in  sawdust  must  be  considered,  as  well 
as  the  labor  cost  of  sawing.  The  comparison 
would  have  to  be  made  between  the  yields  in  a 
given  time,  and  the  cost  of  preparation.  It  is 
generally  supposed  that  the  resins  and  products 
of  distillation  exude  from  the  ends  of  the  piece, 
so  the  more  pieces  there  are,  there  will  be  twice 
as  many  ends.  This  is,  to  a  large  extent,  true, 
and  it  would  be  supposed  that  to  hog  it  would 
make  it  infinitely  better  for  distillation.  While 
this  is  true  as  regards  the  removal  of  the  turpen- 
tine, yet  when  destructive  distillation  sets  in,  the 
process  not  only  does  not  work  smoothly,  but  the 
material  next  to  the  shell  of  the  retort  can  be  thor- 
oughly charred  and  the  interior  not  charred  at  all. 
However,  the  author  finds  that,  although  more 
products  of  decomposition  come  out  at  the  ends, 
yet  a  considerable  portion  comes  out  over  the  en- 
.tire  surface.  It  would  be  necessary,  probably, 
to  make  a  definite  test  at  each  plant  to  ascertain 
the  best  conditions. 


It  may  be  doubtful  sometimes  what  to  use  for 
fuel,  some  recommending  using  the  charcoal  pro- 
duced when  a  destructive  distillation  process  is 
used;  others  crude  oil;  some  sawdust,  and  some 
wood.  Not  that  which  is  the  cheapest,  but  that 
which  is  of  the  least  value  to  the  plant  should 
be  used.  For  instance,  charcoal  might  be  made 
for  $5  per  ton,  and  be  cheaper  than  coal  at  $8 
per  ton,  but  if  charcoal  could  be  sold  for  $10  per 
ton  it  would  be  of  more  value  to  the  plant  to 
sell  it  than  to  burn  it  in  preference  to  coal.  In 
the  same  way,. it  might  cost  ?1  per  ton  to  make 
the  residue  from  the  steam  process,  and  this 
would  be  cheaper  than  wood  as  fuel  at  $2  per  ton; 
but  if  the  residue  could  be  sold  for  $3  per  ton 
for  making  oxalic  acid,  then  the  residue  would 
be  of  more  value  to  the  plant  if  sold  than  if  burnt 
for  fuel.  This  method  of  calculation  is,  of  course, 
very  familiar. 

The  quantity  of  fuel  used  by  the  different  proc- 
esses per  cord  of  wood  varies  with  the  dryness 
and  the  amount  of  pitch.  Information  concerning 
this  is  not  easily  ascertained.  In  the  hardwood 
industry  certain  facts  are  definitely  known  rela- 
tive to  the  fuel  used  per  cord,  and  for  pine  wood 
it  is  considerably  more.  The  fuel  proposition  at 
most  wood  plants  is  a  serious  one  unless  favor- 
ably located. 

In  the  steam  process  distilling  sawdust  with  a 
yield  of  one  to  three  gallons  per  ton  with  a  dis- 
tillation period  of  one  hour,  it  is  claimed  by  those 
making  such  distillations,  that  it  requires  only 
about  one-quarter  of  the  residue  for  fuel.  This 
looks  rather  low.  Using  fat  wood  yielding  fifteen 
to  eighteen  gallons  per  cord,  with  a  distilling 
period  of  three  hours,  it  takes  about  all  the  resi- 
due as  fuel  to  furnish  steam  for  the  operation. 

In  the  steam  and  distilling  process  it  is  claimed 
that  only  one  cord  of  wood  is  required  as  fuel  for 
each  cord  of  wood  distilled.  One  plant,  however, 
using  arches  to  protect  the  retort,  distilling  wood 
yielding  ten  gallons  of  turpentine  to  the  cord, 
with  a  distilling  period  of  twenty-four  hours,  took 
21/2  cords  of  slabs  to  use  as  fuel  to  distill  the 
wood,  pump  the  condensing  water  and  furnish 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


115 


lights,  etc.,  and  when  oil  was  submitted  as  fuel 
it  required  6.4  barrels  per  cord  to  furnish  the  nec- 
essary heat  for  the  above  purposes.  This  plant 
used  cars  for  drawing  out  the  charcoal. 

In  the  hardwood  industry  small  retorts  use 
about  500  pounds  of  soft  coal,  plus  the  tar  pro- 
duced per  cord  of  wood  distilled,  the  coal  equal 
to  about  one-half  a  cord  of  wood.  The  large  ovens 
require  from  5,000  to  8,000  cubic  feet  of  natural 
gas,  30,000  cubic  feet  of  this  being  equal,  approxi- 
mately, to  a  ton  of  coal. 

From  this,  it  seems  that  results  are  apt  to  vary, 
and  only  a  general  rule  can  be  given.  For  the 
steam  process  about  one  quarter  to  three-quarters 
of  a  cord  of  fuel  per  cord  of  wood  distilled,  and  for 
the  destructive  process  on  pine  wood  from  one  to 
two  cords  of  wood,  or  its  equivalent,  according  to 
the  construction  of  the  furnace  and  the  process 
used. 

The  next  consideration  is  the  kind  and  quantity 
of  apparatus  needed,  and  this  is  determined  by  the 
process  used  and  the  yield  per  cord;  fat  wood 
taking  longer  to  distill,  thus  requiring  more  ap- 
paratus for  a  given  caoacity. 

Using  the  steam  process  for  sawdust  and  slabs, 
a  plant  independent  of  a  saw  mill  would  need 
boilers  of  sufficient  capacity  to  furnish  steam  for 
distilling,  pumping  water  and  running  the  engines 
for  the  conveyors  and  bog,  as  well  as  any  stirring 
apparatus  used  in  the  retort.  The  size  of  this 
apparatus  is  determined  by  the  quantity  of  raw 
material  to  be  utilized  per  day. 

With  some  processes  it  is  best  to  build  in  the 
form  of  units,  having  the  units  as  large  as  pos- 
sible to  make  economical  working.  Take,  for  ex- 
ample, a  vertical  steam  retort  with  an  opening  at 
the  top  for  charging  and  a  door  at  the  bottom  for 
discharging;  it  can  be  readily  seen  that  if  all  the 
work  was  to  be  done  in  one  of  these,  that  cases 
might  arise  in  which  it  would  take  special  ma- 
chinery to  raise  and  lower  the  doors,  whereas  if 
made  in  smaller  units  they  could  be  easily  oper- 
ated by  hand,  or  by  means  of  simple  contrivances. 
Under  certain  conditions  in  using  a  very  large  re- 
tort, by  letting  in  only  a  small  amount  of  steam, 


the  whole  might  condense  without  doing  any  work. 
Except  in  those  cases  where  the  labor  cannot  be 
used  to  advantage,  it  would  seem  advisable  to  use 
as  large  retorts  and  condensers  as  possible,  con- 
sistent with  continuous  working.  Where  the  work 
can  be  performed  better  in  alternate  retorts,  then 
half  the  size  would  be  better,  two  units  being  used. 
The  steam  process,  taking  from  only  one  to  six 
hours,  has  the  advantage  over  the  others,  in  that 
a  night  crew  is  not  necessary. 

All  steam  processes  ought  to  extract  the  oil 
equally  well  with  the  same  conditions  of  steaming. 
The  difference  would  be  in  the  time  of  steaming, 
and  it  is  to  be  expected  that  those  processes  which 
stir  the  wood  would  give  the  quickest  and  best 
yield.  For  this  reason,  rotary  retorts  are  in  use, 
and  if  the  saving  in  time  or  increase  in  yield  war- 
rants the  additional  initial  cost,  they  wfii  be  much 
used.  But  the  essential  difference  in  the  steam 
process  must  be  in  the  method  of  handling  the 
raw  material,  and  an  examination  of  the  plans  of 
the  proposed  process  will  enable  one  to  judge  of 
its  merits  in  this  direction.  In  making  estimates 
on  all  plants,  plenty  of  margin  should  be  allowed 
for  unforeseen  contingencies,  particularly  as  to 
the  yield,  the  amount  of  fuel  used  and  the  condi- 
tion of  the  market. 

If  it  has  been  decided  tbat  charcoal  should  be 
made,  then  choice  should  be  made  of  a  steam  and 
destructive  process  or  a  destructive  process  with- 
out steam.  Perhaps  the  most  important  thing  to 
consider  in  connection  with  these  processes  would 
be  the  method  of  handling  the  charcoal  produced. 
Those  processes  that  arrange  for  the  removal  of 
the  charcoal  while  the  retort  is  hot  are  to  be  pre- 
ferred. There  is  a  great  saving  in  fuel,  and  also 
in  time. 

Ordinary  destructive  distillation  in  one  cord  re- 
torts ought  to  take  from  twenty-one  to  twenty-two 
hours,  thus  enabling  the  contents  of  each  retort 
to  be  distilled  once  in  twenty-four  hours.  Some 
attempt  to  complete  the  distillation  in  less  time 
than  that,  but  the  damage  to  the  retort  is  very 
severe.  The  use  of  cars  is  practiced  in  ovens  and 
large  retorts,  but  in  order  to  make  them  of  suf- 


116 


TEH    UTILIZATION    OF    WOOD    WASTE,    BY    DISTILLATION. 


ficient  rigidity,  it  is  necessary  to  make  them  of 
such  a  thickness  that  they  affect  the  heating  value 
of  the  retort.  This  can  be  readily  observed  In 
those  cars  open  at  the  top  and  less  open  at  the 
bottom.  In  this  case  the  wood  is  often  found  to 
be  charred  at  the  top  of  the  car  and  only  partially 
so  at  the  bottom,  and  this  when  the  heat  is  ap- 
plied to  the  bottom. 

But  when  the  wood  is  placed  directly  in  contact 
with  the  walls  of  the  retort,  the  quality  of  the  tur- 
pentine   is    impaired,    so    some    means    should    be 
devised  to  keep  the  wood  from  coming  in  contact 
with  the  walls  of  the  retort  and  at  the  same  time 
serve  to  remove  the  charcoal.    Perhaps  more  open- 
work cars  provided  with  a  means  of  scraping  the 
trash  and  fine  charcoal  from  the  bottom  of  the  re- 
tort upon  their  exit,  may  prove  satisfactory.     On 
account  of  the  deposit  of  coke  on  the  bottom  of 
the  retort,  which  is  the  residue  from  the  distilled 
tar  which   drops   from   the  bottom   of  these  open- 
work  cars,   a   long   retort  is  difficult  to  clean  out 
while  hot,   and   as   they   must   be   cleaned   to   pre- 
vent burning  of  the  bottom,  the  process  used  must 
provide  a  means  for  the  removal  of  this  material. 
The  use  of  large  or  small  retorts  is  a  question  at 
issue  with   pine   wood   distillers.     If  small   retorts 
were  used  cars  would  not  be  advisable,  as  they 
occupy  relatively  too  much  space,  and  full  advan- 
tage of  the  capacity  of  the   retort  cannot  be   ob- 
tained.     However,    other   things    being    equal,    the 
author,  although  preferring  small   retorts  in  most 
instances,  sees  no  reason  why  a  large  retort  con- 
structed   upon    the    same    principles    as    the    long 
ovens  used  in  the  hardwood  industry,  and  fired  by 
crude  oil  or  natural  gas,  would  not  give  as  good 
satisfaction    with    pine    wood    as    with    hardwood. 
Exactly  the  same  principles  would  govern  the  fir- 
ing, and  it  would  be  only  necessary  to  use  a  cor- 
respondingly large  quantity  of  superheated  steam 
during  the  first  part  of  the  operation  to  carry  off 
the  turpentine  vapors.     It  would  take  about  8,000 
cubic   feet  of  natural   gas    per   cord   to   distil   the 
charge    in    such    an    oven.      In    these    cases    cars 
could  be  used  as  found  in  the  hardwood  industry. 
The   use   of   an   oven   brings   forth   the   question 


of  furnace  construction  and  the  cost  of  fuel.  There 
is  no   doubt  that  the   cost   Of  charring  in   cars   is 
greater  than   without   their   use,   but   the   question 
of  using  an  arch  to  protect  the  retorts  from  the 
injurious  action  of  the  fire  gases  is  much  agitated. 
II  has  been  found  at  a  steam  and  destructive  dis- 
tillation  plant   using   retorts   seventeen    feet    long, 
set   in   a  furnace   with   return   flues,   that  if  prop- 
erly made  the  furnace  arches  stood  very  well,  but 
if  they  became  out  of  order  for  any  reason  they 
would   fall  in   at  the  most   critical  periods  of  the 
distillation  and  allow  the  flame  to  severely  injure 
the  retort.     Furthermore,  the  fuel  used  was   over 
twice   as   much   as  is  usually  used   when  no   arch 
is  present.     Firing  with  crude  oil  over  six  barrels 
was  necessary  to  distill  one  cord  of  medium  rich 
wood,   when    without   an    arch    one    cord    of   wood 
would  be  sufficient.     It  would  seem  that  with  short 
retorts    the    use    of    the    arches    below    the    retort 
causes  the  heat  to  go  up  the  chimney,  whereas  in 
a  long  oven  the  heat  of  the  fuel  would  be  better 
absorbed   by   the   brickwork,   owing  to   the   longer 
time  of  contact.     It  is  on  this   account,  probably, 
that  arches   are  found   under  some  of  the   50-foot 
ovens    used   in   the   hardwood    industry,    and   none 
under    the    9-foot    cylindrical    retorts.      It      would 
seem    that   in    the    latter    case    the    retorts    would 
rapidly   burn    through,   but   this   seems    to   depend 
upon   the  firing,   as   a   Florida   company   has   used 
some   for   three   years   and   a   Northern    hardwood 
company   used    some   continuously   for   five    years, 
and  only  one  out  of  seven  had  needed  to  be  even 
turned   in  that   time.     On  the  other  hand,   at  the 
game   place   a  whole  set  had   been  burned  out  in 
less   than   a  year.     As   an   oven   is   so   difficult  to 
replace,   it  is   advisable   to   protect  them   to   some 
extent.     An  arch  as  long  as  it  stands   and  is  not 
in   direct   contact   with   the   iron   of   a   retort   will 
undoubtedly  protect  the  retort,  and  in  those -cases 
where  the   fuel   is   cheap  enough  to   allow   it,  the 
arch  could  be  advantageously  used. 

The  next  feature  to  consider  in  judging  the 
process  for  the  production  of  turpentine,  tar  and 
charcoal  is  the  quality  of  the  turpentine  pro- 
duced. Although  the  refining  of  the  crude  prod- 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


117 


net  is  perhaps  the  most  essential  thing,  connected 
with  the  quality  of  the  oil  produced,  nevertheless 
those  processes  that  do  not  take  off  the  turpen- 
tine before  destructive  distillation  begins  and  col- 
lects it  in  a  separate  receiver,  are  obviously  at  a 
disadvantage  as  far  as  quality  is  concerned.  When 
rosin  in  distilled  rosin  spirit  is  produced,  and 
this  is  usually  found  in  the  turpentine  produced 
when  the  receiver  is  not  changed,  consequently 
this  turpentine  is  not  as  good  as  it  would  be  if  it 
did  not  contain  this  substance.  If  th-is  kind  of  oil 
can  be  sold  at  the  same  price  as  better  qualities, 
and  it  has  been  so  far,  then,  of  course,  it  is  not 
desirable  to  separate  the  rosin  spirit;  but  the 
time  is  coming  when  only  the  pure  terpene  can  be 
sold  at  a  high  price,  while  the  mixtures  must  be 
sold  for  less. 

At  the  present  time  it  is  necessary  to  have  a 
colorless,  agreeable  smelling  oil,  and  this  should 
bo  sought  for. 

Special  processes  can  be  judged  by  their  claims, 
and  these  are  given  in  connection  with  the  process. 

Extraction  processes  might  be  made  to  pay  after 
the  market  is  established,  but  their  final  success 
will  depend  largely  upon  the  demand  for  the  rosin 
and  rosin  oil. 

Market  Conditions. — The  most  important  prob- 
lem connected  with  the  distillation  of  pine  and  fir 
wood  is  the  disposal  of  the  products.  If  interested 
parties  would  spend  their  money  advertising  wood 
turpentine,  instead  of  augmenting  the  patent  of- 
fice receipts  by  obtaining  useless  patents,  much 
more  could  be  done  toward  solving  the  problem  at 
hand.  There  are  plenty  of  good  processes,  and 
they  will  yield  a  product  of  the  finest  quality  if 
handled  right. 

A  great  deal  has  been  written  about  the  ignor- 
ance of  the  men  who  produce  wood  turpentine, 
but  far  more  could  be  written  of  the  ignorance  of 
consumers  and  buyers.  A  sample  of  nearly  chem- 
ically pure  pinene  was  sent  to  a  buyer  of  a  lead- 
ing varnish  company,  and  the  sample  returned  as 
not  satisfactory.  Instead  of  testing  the  oil,  the 
cork  was  removed  and  judgment  passed  on  the 


odor.  This  oil  could  not  be  duplicated  at  less  than 
twice  the  price  of  ordinary  turpentine. 

Complaints  are  made  concerning  the  variation 
in  quality,  but  there  is  also  a  variation  in  the  qual- 
ity of  gum  spirits.  By  having  storage  tanks  of 
sufficient  size,  a.  standard  grade  from  each  plant 
can  be  readily  obtained.  But  what  is  the  use  of 
making  a  very  good  quality  of  turpentine  when  it 
does  not  command  any  better  price  than  an  in- 
ferior quality?  Thousands  of  gallons  of  slightly 
yellow  oil  have  been  sold  which  would  have  been 
refined  if  the  price  had  warranted  it.  Only  so 
much  could  be  obtained  for  it,  good  or  bad.  With 
a  standard  grade  made  by  some  of  the  methods 
herein  given,  the  large  varnish  and  paint  houses 
can  be  easily  convinced  of  the  merits  of  this  tur- 
pentine. The  painter  is  the  most  difficult  to  per- 
suade; the  least  variation  in  the  odor  at  once 
makes  him  suspicious.  One  painter  using  wood 
turpentine  painted  a  house  with  white  lead  and 
added  a  Japan  dryer  containing  some  sulphuric  acid 
so  that  the  paint  would  dry  quickly.  The  dirty 
looking  house  produced  was  laid  to  the  turpentine, 
instead  of  the  wrong  kind  of  dryer. 

The  consideration  of  the  market  for  turpentine 
needs  no  further  illustrating  than  the  fact  that 
Chicago  paint  manufacturers  are  using  thousands 
of  gallons  of  it,  and  claim  that  it  works  better. 
However,  there  is  ho  indication  of  their  being 
willing  to  pay  the  market  price  for  it.  On  the 
other  hand,  varnish  makers  have  not  found  a 
wood  turpentine  but  what  it  varies  too  much  to 
suit  their  requirements. 

What  applies  to  the  turpentine  market  also  ap- 
plies to  the  tar  market.  Here  tkwre  is  more  ex- 
cuse for  complaint,  for  the  retort  tar  is  not  al- 
ways as  good  as  it  might  be.  With  a  little  care, 
so  that  the  resinous  and  oily  products  will  be  left 
in  the  tar,  this  product  could  be  made  of  a  qual- 
ity satisfactory  to  cordage  manufacturers.  It 
should  be  sold  more  by  viscosity  than  it  is,  as 
some  tar  of  the  required  specific  gravity  is  really 
too  thin. 

The  market  for  tar  is  limited,  but  with  the 
prominence  now  being  given  to  steam  processes, 


118 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION, 


the    supply    is    apt   to    be    lessened,    thus    causing 
a  prospect  of  a  better  price. 

With  charcoal  the  market  is  entirely  local,  al- 
though some  sell  to  blast  furnaces  at  a  distance. 
The  price  of  charcoal  is  easily  ascertained,  but  the 
consumption  cannot  be  easily  determined. 

A  comparison  of  the  cost  of  operating  by  the 
various  processes  will  be  given  below.  Different 
values  can  be  substituted  to  suit  the  special  con- 
ditions, the  ones  given  below  being  only  approxi- 
mate. In  the  steam  process  using  sawdust  a  value 
must  be  placed  on  the  residue  used  for  fuel,  as 
in  many  cases  this  could  be  sold.  A  steam  plant 
uses  so  much  more  wood  in  a  given  time  that  a 
given  supply  would  be  much  sooner  exhausted  than 
with  a  destructive  distillation  plant.  It  is  not  nec- 
essary to  operate  a  steam  plant  at  night,  as  a  dis- 
tillation can  be  completed  in  three  hours,  but  it 
is  necessary  to  operate  at  night  with  a  destructive 
distillation  process,  as  it  takes  about  twenty-two 
hours.  In  twenty-four  hours  a  steam  plant  ought 
to  distill  eight  times  as  much  wood. 
Steam  Plant. 

Plant  and  equipment $25,000 

Depreciation  on  retorts  only  10% $1,200 

Interest  at  6% 1,500 

Operating  expense — 

Depreciation    and    interest,    per    month.. $    233 

2080    cords    wood    at    $3 6,240 

Labor  and  superintendence,   $1  per  cord  2,080 

Total    expense    per    month $8.553 

Expense  per  cord.   $4.112. 

Twelve  Hour  Basis. 

Operating  expense — 

Depreciation   and   interest,    per  month.. $    233 

1040   cords    wood   at   $3 3,120 

Labor  and  superintendence  at  $1... 1.040 


Total    per    month $4,393 

Expenses   per  cord,    $4.224. 

Destructive    Process. 

Plant  and  equipment $25,000 

Depreciation   on  retorts   20% $2,400 

Interest  at  6% 1.500 

Operating  expense — 

Depreciation  and  interest,  per  month $    325 

260  cords  wood  at  $3 780 

Labor,    etc 450 

260   cords   fuel    at   $2 520        .   . 


Yields   per  Cord. 

RICH    WOOD.  LEAN   WOOD. 

15    gal.    turpentine    at  5    gal.     turpentine    at 

50c    $7.50         50c     $2.50 

10  gal.  wood  oil  at  20c     2.00  3  gal.   wood  oil  at  20c       .60 

90  gal.  tar  at  6c 5.40  50  gal.  tar  at  6c 3.fiO 

46  bu.  charcoal  at  lOc     4.60  46  bu.  charcoal  at  lOc     4.60 


$19.50 
Expense   destructive..     7.98 


$10.70 
7.98 


Profit   per  cord $11.52  2.72 

The   steam   process   obtains   turpentine   only,  so 
the  figures  would  be: 


Rich   Wood. 

Yield    $7.50 

Expense    24    hours 4.112 


Lean  Wood. 
$2.50 
4.112 


$2.075 


Expense  per  cord,  $7.98. 


Profit  per  cord $3.388        Loss   ner   cord $1.612 

On   a   yearly   basis   of   250   days. 

Steam    Process — 24    Hours. 

Fat  Wood,  Profit.  Lean  Wood.  Loss. 

20.000  cords  at   $3. 388. $67, 760    20,000  cords  at  $1.612. $32, 240 

Profit    on    $25,000 271%    Loss  on  $25,000 128.96% 

12  Hours. 

10.000  cords  at   $3. 276. $32. 760    10,000  cords  at  $1.50.  .$15.000 
Profit  on  $25,000 131%    Loss  on   $25,000 60% 

There  would  be  considerable  difficulty  in  ob- 
taining 20,000  cords  of  wood  at  $3  per  cord. 

Destructive    Process. 

Fat  Wood.  Profit.                      Lean  Wood,  Profit. 
2500   cords   at   $11. 52. $28, 800    2500   cords   at   $2.72. .  .$6,800 
Profit    on    $25.000 114.2%    Profit  on   $25,000 27.2% 

Figures  for  a  rotary  retort  will  not  be  put  down 
here,  as  they  have  not  been  even  aproximated  with 
this  apparatus. 

From  the  above,  it  can  be  seen  that  the  steam 
process  gives  greater  returns  on  fat  wood  than 
the  destructive  process  in  the  same  length  of 
time.  With  lean  wood  the  reverse  is  apparently 
true,  and  an  actual  loss  might  be  expected  in 
some  cases.  The  apparently  wonderful  returns 
from  the  destructive  process  is  due  to  setting  the 
market  value  on  products  of  a  similar  nature. 
However,  although  prospectuses  relative  to  these 
plants  put  down  these  values,  unfortunately,  the 
market  conditions  are  such  that  often  these  prod- 
ucts cannot  be  disposed  of  at  any  price.  This 
has  been  particularly  true  of  wood  oil  until  re- 
cently, when  it  has  been  disposed  of  to  some  ex- 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


119 


tent  in  creosote  paints.  The  charcoal  is  often  not 
sold  at  all,  or  for  only  half  the  values  assigned  to 
it.  At  one  plant,  however,  the  prices  above  given 
have  been  obtained  in  limited  quantities. 

It  can  be  seen  that  this  problem  of  wood  dis- 
tillation is  not  so  simple  as  it  appears  at  first 
sight.  This  accounts  probably  for  the  number  of 
patent  processes  that  apparently  solve  the  prob- 
lem. Upon  further  investigation  and  the  expendi- 
ture of  considerable  money,  these  processes,  which 
start  out  so  fairly,  prove,  in  most  cases,  to  be  dis- 
mal failures.  Instead  of  building  plants  on  a  com- 
mercial basis  at  the  start,  more  experimenting 
should  be  done  on  a  small  scale  until  all  the  par- 
ticular points  in  a  given  locality  have  been  con- 
sidered, then  a  plant  should  be  built  in  units, 
making  one  unit  pay  before  building  the  next,  and 
so  on  until  the  limit  is  reached. 

It  has  been  found  that  the  profits  of  this  indus- 
try, as  shown  on  paper  before  the  plant  is  built, 
are  far  greater  than  the  actual  working  results,  and 
in  many  cases  the  loss  is  greater  than  the  figured 
profit  was  expected  to  be. 


Owing  to  the  wide  difference  in  proportion  be- 
tween the  percentages  of  resinous  products  in  dif- 
ferent trees  and  in  different  localities 
many  instances  will  be  found  where  it  is  not  pos- 
sible to  operate  plants  of  this  kind  successfully. 
The  variations  in  the  yields  from  a  cord  of  dif- 
ferent pines  and  firs  will  be  found  in  the  next 
chapter. 

Of  the  two  processes,  steam  and  destructive  dis- 
tillation, the  former  is  probably  better  for  fat  wood 
and  for  cheap  wood,  such  as  sawdust.  With  wood 
yielding  small  amounts  of  turpentine,  the  steam 
process  would  not  yield  enough  product  to  pay  for 
the  gathering  of  the  wood,  unless  some  use  is 
found  for  the  residue.  Using  the  destructive  proc- 
ess, with  a  good  demand  for  tar  and  charcoal,  it 
might  be  possible  to  use  such  a  class  of  wood  suc- 
cessfully. The  greatest  advantage  of  a  success- 
ful destructive  distillation  process  would  be  that 
it  takes  so  much  less  wood  to  obtain  products  of 
the  same  value.  With  the  steam  process  a  given 
supply  of  wood  is  too  soon  exhausted. 


CHAPTER  X. 

COMPOSITION  OF  WOOD  AND  PRODUCTS  OF  DISTILLATION. 


Pine  wood  has  a  structure  very  similar  to  other 
kinds  of  wood,  but  substances  peculiar  to  the  pine 
family  are  also  to  be  found. 

Generally  considered,  pine  wood  consists  of  cel- 
lulose or  woody  tissue,  containing  gums,  resins, 
salts,  sap,  etc.,  and  the  outer  bark.  When  wood  is 
spoken  of,  it  immediately  suggests  lumber  or  fuel, 
but  the  uses  of  wood  in  other  lines  will  be  found 
to  be  very  many. 

The  woody  fibre  consists  primarily  of  two  sub- 
stances, cellulose  and  lignin,  the  first  having  the 
formula  n  (Ce  Hio  Os) ;  100  parts  containing  44.45 
parts  carbon,  C.17  parts  of  hydrogen  and  49.38  of 
oxygen.  There  is  also  in  wood  recently  cut  a . 
large  percentage  of  water,  amounting  in  some 
cases  to  as  much  as  45  per  cent.  Air-dried  wood 
generally  has  about  20  per  cent  moisture.  All  this 
can  be  evaporated  from  the  wood  by  heating  it  at 
105  degrees  to  110  degrees  C.  for  a  sufficient  length 
of  time,  but  it  will  reabsorb  practically  the  same 
amount  when  again  exposed  to  the  air.  Very  fat 
pine  contains  less  than  10  per  cent  moisture. 

Pine  wood  has  a  specific  gravity  of  from  0.55  to 
about  1.15,  being  in  the  latter  case  very  fat  or 
pitchy.  Usually  the  fat  wood  is  harder  than  the 
other  and  does  not  decay  so  rapidly. 

The  composition  of  nearly  all  kinds  of  wood  is 
relatively  the  same,  provided  they  be  dry  and  con- 
tain no  large  amount  of  resins  and  gums.  This 
average  is  49.70  per  cent  carbon,  6.06  per  cent  hy- 
drogen, 41.30  per  cent  oxygen,  1.05  per  cent  nitro- 
gen and  1.80  per  cent  ash.  This,  of  course,  would 
not  apply  to  fat  pine.  By  extracting  the  resin,  the 
fibre  left  would  be  nearer  to  the  above  composition 
than  the  original  wood. 

The  most  important  part  of  pine  wood  to  a  dis- 
tiller is  the  resin.  This  contains  the  turpentine 
and  the  more  resin,  the  more  oil  and  tar.  In  the 
pines  the  resin  fills  in  the  space  between  the  cells. 


In  other  woods  water  is  found  in  the  porous  part, 
but  in  the  pine  the  resin  takes  the  place  of  this 
water  to  a  large  extent.  It  is  difficult  to  deter- 
mine the  amount  of  water  in  fat  pine  on  account 
of  the  turpentine  evaporating  with  the  water  when 
the  wood  is  heated. 

The  resin  seems  to  be  of  two  kinds,  that  con- 
tained in  the  heart  wood  and  that  contained  in  the 
sap.  Although  the  exact  physiology  of  the  forma- 
tion of  resin  in  a  tree  is  not  known,  it  is  gener- 
ally supposed  to  be  due  to  the  infiltration  of  the 
sap  resin  into  the  heart  wood  of  the  tree.  This 
resin  loses  its  fluidity  and  is  not  drawn  out  by  tap- 
ping the  tree.  The  difference  in  the  odor  of  the 
turpentine  produced  from  the  tapped  tree  and  that 
produced  by  distilling  the  wood  itself  is  probably 
due  to  the  odors  of  the  different  impurities  in  these 
oils,  .coming  from  the  different  resins.  Special 
investigations  by  the  Forest  Service  have  shown 
that  the  distribution  of  resin  throughout  the  tree 
from  top  to  bottom  follows  no  law,  the  larger 
amounts  being  found  as  often  in  the  top  or  middle 
portions  as  in  the  butt-logs.  Nevertheless  the  im- 
pression prevails  that  there  is  more  resin  in  the 
stump  and  this  impression  seems  to  have  sufficient 
basis  to  be  a  fact. 

The  cause  of  the  formation  of  resin  in  the  pine 
is  not  easy  to  explain;  resin  passages  arise  from 
the  shrinking  away  from  each  other  of  the  walls 
of  neighboring  rows  of  cells,  an  intercellular  space 
being  thus  formed  and  gradually  filling  up  with 
products  of  decomposition  and  secretion  which  is 
called  resin.  These  resin  passages  are  found  even 
during  germination  and  continue  to  form  until  the 
tree  dies.  It  is  claimed  that  this  formation  con- 
tinues after  the  death  of  the  tree,  an  example  be- 
ing given  of  the  change  of  old  stumps  into  light 
wood.  It  may  be  that  after  the  tree  is  cut  down, 
the  sap  rises  each  year  and  remains  in  the  wood 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


121 


and  finally  when  the  roots  die,  this  resinification 
ceases.  It  takes  so  long  for  a  stump  to  decay  that 
the  evidence  of  the  presence  of  additional  resin 
after  death  could  not  be  well  proven  unless  the 
stump  was  specially  marked  at  the  time  the  tree 
was  cut. 

According  to  the  evidence  of  Prof.  Tschirch,  of 
Switzerland,  who  has  made  recent  investigations 
of  the  causes  of  resin  secretion,  the  seat  of  resin 
secretion  is  in  a  mucilaginous  layer  lining  the  in- 
ner walls  of  the  resin  ducts.  These  ducts  are 
present  in  the  untapped  tree,  but  many  more  of 
a  secondary  nature  are  formed  when  the  tree  is 
tapped.  The  latter  effect  seems  to  be  an  effort 
of  nature  to  heal  the  wound.  This  evidently  shows 
that  the  production  of  resin  during  the  life  of  the 
tree  is  not  a  product  of  resolution. 

If  the  resin  is  formed  by  the  decomposition  of 
the  cellulose  and  starch  while  the  tree  is  growing, 
the  production  of  hydrocarbons  from  carbohydrates 
by  a  change  in  cell  growth  is  demonstrated,  as 
well  as  the  production  of  the  compounds  found  in 
the  tar, 'by  means  of  the  destructive  action  of  heat. 

On  the  application  of  a  moderate  heat  to  the 
wood,  this  resin  exudes.  Considerable  heat  is  nec- 
essary to  draw  all  the  resin  on  account  of  the 
capillary  attraction  of  the  woody  fibre.  If  the 
heat  is  sufficiently  increased  or  steam  added,  the 
turpentine  will  distill  from  the  resin,  and  if  the 
heat  be  further  increased,  the  resin  itself  will  dis- 
till. When  not  very  hot,  the  resin  will  hold  the 
turpentine,  which  can  be  removed  by  a  subsequent 
distillation  with  steam  or  direct  heat. 

This  resin  contains  turpentine,  some  pine  oil, 
resin  oil  and  rosin.  It  is  soluble  in  ether,  alcohol, 
carbon  bisulphide,  etc.  Alkalies  unite  with  it  to 
form  partially  soluble  compounds.  Strong  acids 
decompose  it.  Upon  destructive  distillation  the 
turpentine  and  other  oils  distill  and  the  rosin  is 
decomposed  into  rosin  spirit,  rosin  oil,  gas  and 
pitch.  The  specific  gravity  varies  from  .8  to  1.15. 

After  the  resin  is  removed  from  wood,  w^iat  is 
left  is  mostly  woody  fibre,  consisting  chiefly  of 
cellulose. 

To   obtain   cellulose  pure   from   the   woody  fibre, 


it  is  necessary  to  treat  the  wood  with  various  solv- 
ents such  as  ether,  alcohol,  dilute  acid  and  alkali 
and  finally  wash  with  water.  Cellulose  is  a  carbo- 
hydrate and  thus  in  this  respect  is  similar  to  starch 
and  sugar  and  although  it  cannot  be  converted  into 
starch  it  may  be  changed  into  sugar.  This  feature 
is  interesting  as  it  is  possible  to  make  ethyl  alco- 
hol from  the  sugar  produced. 

Acids  and  alkalies  affect  cellulose;  hydrochloric 
acid  forms  hydro-cellulose  and  wood  sugar,  nitric 
acid  produces  nitro-cellulose  and  other  products  of 
oxidation  according  to  the  strength  of  the  acid 
used.  Strong  solutions  of  alkalies  affect  it;  caus- 
tic soda  being  used  to  mercerize  cotton,  while 
melted  caustic  alkalies  change  it  into  oxalic  acid, 
this  being  another  important  reaction  of  particu- 
lar value  in  treating  sawdust.  A  mixture  of  cup- 
ric  oxide  and  ammonia  known  as  Schweitzer's  re- 
agent, dissolves  cellulose,  and  the  addition  of  acid 
to  this  solution  causes  a  flaky  precipitate. 

Viscose  is  a  compound  of  cellulose  formed  by 
treating  calico  (cotton)  with  strong  soda  or  pot- 
ash and  washing  with  alcohol.  These  compounds 
treated  with  carbon  bisulphide  C  82  form  thio- 
carbonates  which  are  soluble  in  water.  The  vis- 
cous solution  of  these  thiocarbonates  is  called  vis- 
cose. 

To  the  distiller,  the  most  interesting  feature  con- 
nected with  the  treatment  of  wood  is  its  decompo- 
sition by  means  of  heat.  The  main  products  pro- 
duced are  pyroligneous  acid,  gas  and  resinous  prod- 
ucts, wood  alcohol,  wood  oil  or  red  oil,  tar,  and 
charcoal. 

Below  is  given  a  list  of  the  various  substances 
that  may  be  expected  from  destructive  distillation 
of  pine  wood  containing  resin.  This  list  will  ex- 
plain why  refining  some  of  the  products  might  be 
expected  to  be  difficult.  Charcoal  is  the  residue. 

Gases. 

Carbondioxide,  carbon  monoxide,  .hydrogen,  me- 
thane, acetylene,  ethylene,  propylene,  butylene,  pen- 
tine,  benzol. 

Wood  Oil   and   Tar. 

Benzol,   toluol,   xylol,   styrolene,  naphthalene,   re- 


122 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


tene,  paraffine,  dimethyl  ethers  of  pyrogallic  acid, 
methyl  pyrogallic  acid  and  propylpyrogallic  acid, 
phenol,  the  three  creosols,  the  xylenols  (1,  3,  4  and 
1,  3,  5)  phloral,  pyrocatechin,  orthoethyl  phenol, 
guaiacol,  pyrogenous  resins,  pinene,  sylvestrene, 
dipentene,  amylene,  hexylene,  pentane,  toluene  hex- 
ahydride,  toluene  tetrahydride,  xylene  hexahydride, 
xylene  tetrahydride,  xylene,  cumene  hexahydride, 
cumene  tetrahydride,  cumene,  terebenthene,  cy- 
mene  hexahydride,  metiso-cymene,  metapropyl- 
ethyl  benzene,  dioctene,  diterebentyl,  diterebenty- 
lene,  didecene,,  propionic  aldehyde,  furfural  and 
methyl,  furfural,  methylfurfural,  dimethylfurfurane, 
trimethyl  furfurane,  pyroxanthine. 

Wood  Vinegar  and  Wood   Alcohol. 

Furfural,  formic  acid,  acetic  acid,  propionic  acid, 
butyric,  valerianic,  capronic,  crotonic,  angelicic  and 
caproic  acids,  valerolactone,  pyrocatechol,  methyl 
alcohol,  methyl  acetate,  acetone,  methyl  formate, 
methylethylketone,  allyl  alcohol,  dimethyl  ace- 
tate, acetic  aldehyde,  methylamine,  ethyl  alcohol, 
hydrocoerulignon,  allyl  alcohol,  isobutyl  alcohol, 
isoamyl  alcohol,  methylpropylketone,  ketopenta- 
methylene  or  cyclopentanone  or  odipic  ketone,  ke- 
tohexamethylene  or  pimelic  ketone.  Alpha- 
methyl-Beta-ketopentamethenylene,  pyridine,  methyl 
pyridine,  valeraldehyde,  allyl  alcohol  and  water. 

Residue. 

Charcoal,  containing  carbon,  hydrogen  and  oxy- 
gen and  mineral  matter. 

When  wood  is  first  heated  in  a  retort,  only  water 
and  a  little  furfural  are  driven  off  until  the  tem- 
perature reaches  150  degrees  C.  With  fat  pine, 
some  oil  also  comes  over.  As  the  temperature  ap- 
proaches 160  degrees  C.  decomposition  sets  in,  the 
entire  loss  in  weight  of  the  wood  from  150  degrees 
to  ICO  degrees  being  only  about  2  per  cent,  most  of 
which  is  water.  This  latter  temperature  corre- 
sponds to  about  320  degrees  Fah. 

The  following  table  shows,  according  to  Violette's 
tests,  the  relative  percentage  loss  at  the  different 
temperatures: 


Temp.  C 150°     150-160°  160-170°     170-180° 

Loss  per  cent,  water  only      2  5.5  11.4 

150-280°     280-350°  150-430°  430-1500° 
63.8             6.5  81.  1.7 

At  first  only  a  small  amount  of  acetic  acid  comes 
over,  but  the  percentage  increases  gradually  until 
the  temperature  reaches  about  280  degrees  C., 
when  the  proportion  of  acetic  acid  diminishes.  At 
a  temperature  of  about  325  degrees  C.  (617  degrees 
Fah.)  a  sudden  formation  of  gas  takes  place  and 
the  temperature  increases  rapidly  to  375  degrees 
C.  (707  degrees  Fah.),  the  extra  heat  being  caused 
by  the  decomposition  of  the  wood. 

When  the  temperature  reaches  about  430  degrees 
C  (806  degrees  Fah.)  most  of  the  volatile  matter  is 
distilled  and  only  charcoal  remains  in  the  retort. 
With  some  woods  containing  large  amounts  of  par- 
affines,  they  are  not  distilled  under  535  degrees  C. 
(998  degrees  Fah.). 

Why  cellulose  breaks  into  so  many  different 
products  when  distilled,  it  is  difficult  to  state.  The 
molecule  is  very  complex,  and  it  is  probably  on 
account  of  the  large  number  of  atoms. 

An  explanation  of  the  process  is  given  by  Mills, 
in  his  use  of  the  term  cumulative  resolution.  In- 
stances of  this  are  very  common  in  inorganic  chem- 
istry, one  example  of  which  he  gives  in  the  case 
of  manganese  dioxide  splitting  up  when  heated  into 
trimanganic  tetroxide  and  oxygen  according  to  the 
following: 

3  Mn  O2  =  Mn3  O*  +  O2. 

With  woody  fibre,  water  instead  of  oxygen  is 
lost,  and  new  products  formed.  As  the  temperature 
increases  more  water  leaves.  The  following  is 
Mill's  illustration: 


Cellulose  Alcoholoids. 

Ca      Hio      Os 
Ca      Hs       C>4 

Ce     Ha      Os 

Ca      H*        O». 

C«     H2      O 


Extreme  Accumulation. 
Ce     H8     O* 
C«     H8     O3 

Ca      Ht      O2 

C.     H2     O 
C. 


It  will  be  noticed  that  each  product  is  formed  by 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


123 


the  loss  of  one  molecule  of  water,  H=  O,  from  the 
compound   above   it. 

Although  this  may  be  the  mode  of  decomposition, 
the  final  results  would  be  better  expressed  approx- 
imately as  occurring  as  follows: 
C«     H,o     Os     =     3C       +       4     H2     O     +     Cs     H2     O 
Wood  Carbon  Water          Gas  and  Tar 

100  22.2  44.5  33.3 

From  the  gas  formed  something  can  be  deter- 
mined in  regard  to  the  progress  of  the  distilla- 
tion. When  large  proportions  of  oxygen  are  pres- 
ent, as  in  the  early  stages,  an  abundance  of  car- 
bon dioxide  C  O»  is  found  in  the  gas;  later,  car- 
bon monoxide  C  O  is  found,  and  finally  the  heavier 
hydrocarbons  and  hydrogen.  The  presence  of 
hydrogen  is  probably  due  to  the  degrading  of  the 
hydrocarbons  while  hot. 

Methane,  C  H4  loses  hydrogen  and  becomes  by 
equation 

2   C   H«  =  C2   H2  +   H. 
and  when  very  greatly  heated 

C  H*  =   C  +   H4 

In  a  similar  manner  the  formation  of  some  of 
the  other  hydrocarbons  found  in  the  gaseous  prod- 
ucts may  have  been  produced  according  to  the 
following  reactions: 

3  Cfe    H*    =    2    Ct    H.    +    2    C    H« 
Ethylene  Acetylene          Methane 

4  CL     H<    =     2     C2     H2     +     3     C     H*     +      C 
Ethylene  Acetylene          Methane     Carbon 
2     C     H4     +     CO     =     C3     H8     +     H2Q 
Ethylene  Carbon  Oxide  Propylene  Water 

10     CH*    =     Cio     H8     +     H32 
Methane        Naphthalin     Hydrogen 
The  presence  of  acetic  acid  in  the  distillate  is 
supposed  to  be  due  chiefly,  and  the  methyl  alcohol 
wholly,  to  the  decomposition  of  the  vascular  matter, 
and   not   of   the   cellulose.     The   properties   of  the 
many  products  of  distillation  cannot  be  given  here, 
as  only  a  few  are  of  sufficient  importance.     A  de- 
scription of  only  the  most  valuable  will  be  given. 

Turpentine. 

Oil  of  turpentine  obtained  from  the  gum  of  live 
trees  and  spoken  of  as  gum  turpentine  or  orchard 


turpentine,  has  a  general  formula  of  Cio  Ht«.  It  is 
comprised  of  a  mixture  of  two  or  more  terpenes, 
all  having  the  same  empirical  formula,  but  varying 
In  their  constitutional  or  graphic  formula,  accord- 
ing to  the  method  of  bonding  between  the  carbon 
atoms. 

This  oil  should  be  a  water  white,  light  refracting 
liquid  of  0.8620  to  0.8720  sp.  gr.  and  distilling  be- 
tween 156  degrees  and  170  degrees  C.  It  is  very 
soluble  in  ether,  absolute  alcohol,  carbon  bisulphide, 
essential  oils,  fatty  oils,  benzine,  acetic  acid,  gaso- 
line, chloroform,  etc.  It  is  only  slightly  soluble  in 
water  and  glycerine.  It  oxidizes  very  readily  to 
form  a  thick  oil  and  becomes  "fat"  and  has  an  acid 
reaction. 

Some  grades  upon  vaporizing  increase  in  volume 
193  times,  absorbing  as  latent  heat  74  cal.  per  gram. 
The  vapor  density  air=l  is  5.0130.  Flash  point 
89—94  degrees  F.  Sp.  heat  .472  boiling  point  155 — 
160  degrees  C. 

The  uses  of  turpentine  are  quite  well  known.  In 
addition  to  its  use  in  medicine,  it  is  used  in  paints, 
varnish,  sealing  wax,  shoe  blacking,  etc.  The  three 
kinds  of  turpentine  usually  considered  are  Ameri- 
can, French  and  Russian,  the  French  oil  being  levo 
rotary  and  the  other  two  dextrorotary. 

Terpenes  are  classified  according  to  their  power 
of  absorbing  bromine.  Some  absorb  two  and  some 
four  atoms  of  bromine.  Some  do  not  combine  with 
bromine  at  all.  This  variation  is  supposed  to  be 
due  to  the  different  ethylenic  Unkings.  There  are 
not  as  many  different  terpenes  as  was  formerly 
supposed,  but  there  are  a  large  number  of  hemi- 
terpenes,  sesquiterpenes  and  polyterpenes. 

In  the  oil  from  the  gum  the  chief  constituent 
seems  to  be  pinene.  There  are  three  modifications 
of  this,  varying  according  to  their  action  on  polar- 
ized light.  In  American  and  English  turpentine 
these  rays  are  deflected  to  the  right  and  the  oil 
is  said  to  be  dextrorotary.  In  the  French  oil  it 
is  laevorotary.  An  inactive  form  is  also  found. 
American  oil  of  turpentine  contains  both,  the  dex- 
tro-rotary  being  in  excess. 

This  specific  rotary  power  is  determined  by 
means  of  an  instrument  called  a  polariscope,  the 


124 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


action  of  which  can  be  learned  by  referring  to  treat- 
ises on  chemistry  and  light. 

Another  feature  of  the  terpenes  is  their  power 
to  refract  light.  An  example  of  refraction  is  giv- 
en when  one  end  of  a  stick  is  inserted  in  water. 
The  apparent  bending  of  the  stick  is  due  to  the 
different  degrees  to  which  the  light  from  the  stick 
is  affected  by  water  and  air.  The  refraction  is 
measured  by  the  trigonometrical  relationship  of 
the  refracting  angles.  This  is  done  by  means  of 
some  form  of  refractometer.  It  is  spoken  of  as 
the  refractive  index.  The  working  of  this  instru- 
ment (the  refractometer)  can  be  found  described 
in  works  on  oils  and  fats  and  on  light. 

The  specific  rotatory  power  of  orchard  turpentine 
is  given  as  being  anywhere  from  [a]  D  =  — 3 
to  +  20,  and  the  index  of  refraction  ND  =  1.4682 
to  1.4737  at  20  degrees  C. 

Pinene. 

On  account  of  the  difficulty  of  separating  the 
different  kinds  of  pinene,  some  of  the  constants 
given  are  uncertain. 

The  boiling  point  is  155  degrees  to  156  degrees  C. 
and  the  sp.  gr.  at  20  degrees  C.  0.858  to  0.860. 
Kannonikow  gives  as  the  specific  rotatory  power  of 
pinene  as  to]  D  =  +  32  degrees  for  the  dextro 
and  — 43.4  degrees  for  the  laevo  at  21  degrees  C. 
Rolfe  gives  [c]  D  —  +  45.04  and  — 44.95.  The  in- 
dex of  refraction  at  21  degrees  is  ND  —  1.46553. 


And  Bredt  the  following: 


Wallach  considers  that  pinene  has  an  intercalary 
linking  and  ascribes  to  it  the  formula  below,  which 
equals  Cio  Hi«. 


c     -c 


HC 


CH 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


125 


Dipentene. 

When  pinene  is  heated  to  250  degrees  to  270  de- 
grees C.,  it  is  converted  into  dipentene.  This  sub- 
stance is  inactive  to  polarized  light.  Its  boiling 
point  is  175 — 8  degrees  C.  The  sp.  gr.  at  20  degrees 
C.  is  0.845  and  the  refractive  index  ND  =  1.47308. 
One  form  prepared  from  caoutchouc  boils  at  175 
degrees  to  176  degrees  C.,  and  sp.  gr.  0.844,  and. 
the  refractive  index  N  D  =  1.47194  at  20  degrees. 
This  is  a  very  common  form  of  terpene  and  is 
found  in  many  oils. 

Sylvestrene. 

This  is  found  in  Russian  turpentine  oil.  It  has 
a  very  agreeable  odor  similar  to  lemons  and  also 
to  the  oil  of  bergamot.  It  boils  at  175  degrees  to 
17G  degrees  C.,  has  the  sp,  gr.  of  0.8480  at  20  de- 
grees C.,  and  the  refractive  index  N  D  =  1.47573, 
with  a  specific  rotatory  power  [«]D  =  ~U  66.32. 

The  characteristic  reaction  of  sylvestrene  is 
shown  by  adding  one  drop  of  concentrated  sulphuric 
acid  to  a  drop  of  sylvestrene  in  acetic  anhydride, 
when  a'  blue  color  is  produced.  Another  terpene, 
carvestrene,  shows  the  same  reaction.  This  may 


The  question  is,  what  oil  is  obtained  when  pine 
wood  is  distilled  with  steam  or  direct  heat?  There 
seems  to  be  but  little  doubt  that  it  is  a  terpene  of 
the  formula  do  Hi«.  The  oil  produced  by  steaming 
and  by  destructive  distillation  is  different  in  some 
respects,  and  is  due  to  the  fact  that  the  latter  con- 
tains oils  coming  from  the  decomposition  of  the 
rosin.  When  wood  is  destructively  distilled  and 
the  products  of  decomposition  are  all  collected 
in  the  same  receiver  this  rosin  spirit  and  also  wood 
oil  are  to  be  found  in  the  distillate  and  cannot  be 
satisfactorily  separated. 

The  oil  produced  without  decomposition  of  the 
v/ood  gives  the  tests  for  pinene,  forming  a  solid 
hydrochloride  with  dry  hydrochloric  acid  gas,  and 
having  similar  constants.  In  many  cases,  samples 
of  wood  turpentine  show  more  pinene  than  orchard 
turpentine.  On  the  other  hand,  bad  smelling  colored 
wood  turpentine  shows  tests  for  other  oils. 

Tests  of  fir  terpene  produced  by  distillation  of 
the  Douglas  fir  by  means  of  steam  and  direct  heat 
are  as  follows,  determined  at  the  University  of 
Minnesota: 


be  inactive  sylvestrene.                                                                 Temp-    20    d 
Specific    Gravi 
The  other  terpenes  of  importance  will  be  found 

Boiling-  point 

in    the   following   table.      The    temperatures    given            index  of  refrt 
are  in  degrees  Celsius:                                                               Spec.    Rot.    P< 

degrees    C.               Steam. 

ty        8621 

Destructive. 
.8662 
6  .              157-160 
1.47246 
—29.4 

(degrees)    C  153.5-15' 
iction  1.47299 

jwer  —  47.2 

Terpene. 

Solid 
or          Modifica- 
Liquid.  ,         tions. 
3 

Boiling 
Point. 
155-156 
160-161 
155-156 
175-176 
175-176 
175-176 
178 
185-190 
170 
179-181 
170-172 
173 
175-178 
161-165 
153 
149-150 
162-170 

Specific 
Gravity. 
0.858-0.860 
0.842-0.850 
0.867 
0.846 
0.844 
0.848 

Temp. 
20 
54-48 
20 
20 
20 
20 

19 

22 
18 

Specific  Rotatory 
Power  [<J]D       Temp. 
+45.08  and  —  44.95      21 
and  —  SO.  61      54 
and  —     6.46      20 
+106.8  and  —105.0       20 
Inactive 
+66.32 
Inactive 
Inactive 
+60.33  and  -17.64        19 

Index 
of  Re- 
fraction. 
1.46553 
1.45140 
1.46900 
1.47459 
1.47194 
1.47573 

1.48800 
1.48458 
1.47145 
1.46010 
1.47439 

1.46600 

Tom  p. 
21 
54 

20 
20 
20 
20 

19 
20 
28 
18 
20 

.     S                            3 

3 

<> 

...                    1 

Sylvestrene   

1 

Carvestrene    

1 

Terpinolene    .  .  .  -.  

1 

Phellandrene         ...    . 

2 

0.847 
0.847 
0.836 
0.823 
0.842 

Terpinene    

1 

Thujene    

,  2 

Svnthetical  Terpene.. 

1 

Fenchelene   

1 

Euterpene    

1 

Tricyclene    

.      S                              1 

Bornylene    

,.     S                            1 

Sabinene     . 

1 

0.840 

126 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


Another  terpene  from  the  Norway  pine  investi- 
gated at  the  same  university  gave 

Temp.    20    degrees    C.  Steam.  Destructive. 

Specific  Gravity S636  . 8666 

Boiling   point    (degrees)    C...     153-154  158-160 

Index   of    refraction 1.47127  1.47160 

Specific    Rot.    Power +17.39  +7.56 

Wood  terpene  from  different  samples  of  oil  from 
yellow  pine : 

1  2345 

Specific    Gravity... 0.865-0. 867     0.862     0.862     0.863     0.864 
Boiling  point   C...     155-157  159         156         158         156 

The  author  made  the  following  tests  on  samples 
of  oil.  One  marked  white  oil  is  a  wood  turp,  the 
two  off-color  oils  were  later  distillates  from  the 
same  charge  from  which  the  white  oil  was  ob- 
tained. The  other  two  were  made  from  sawdust 
and  fat  wood.  These  two  oils  were  very  clear  and 
white  and  apparently  well  refined,  and  had 
a  strong  odor  of  sawdust. 


For  fuller  description  of  the  terpenes  see  some 
special  work  under  that  head. 

Pine   Oil. 

This  name  is  applied  to  wood  turpentine  and 
also  to  a  compound  to  which  is  given  the  formula 
C-M  Hio.  This  latter  is  supposed  to  be  formed  when 
pine  wood  is  distilled  at  about  400  degrees  C.  (Pat. 
L.  Pradon,  May  1,  1883).  Another  so-called  pine, 
oil  is  produced,  as  stated  in  Clark's  patent,  previ- 
ously described,  at  240  degrees  to  300  degrees  Fah., 
and  is  a  product  of  the  destructive  distillation  of 
the  wood.  The  term  pine  oil  is  also  applied  to  all 
the  oily  products  of  the  pine  collectively.  Rosin 
spirit  is  sometimes  called  pine  oil. 

Resin  Oil. 

It  has  been  stated  that  the  resin  contains  tur- 
pentine, pine  oil  (?)  resin  oil  and  rosin.  After 
the  turpentine  is  removed  from  the  resinous  crude 


>ff-Color. 


-Sawdust- 


Temperature. 
Specific  Gravity  20/20  

White  Oil. 
0.8654 

Orchard  Turp. 
0.8668 

1 

0.871 

2 

0.888 

1 

0.8762  21/21 

2 
0.890 

Boiling  point   (degrees^   C.. 
Index   of    refraction  

156.5 

1.4721 

158.25 
1.4732 

159 
1.4715 

157 
1.4748 

160 
1.4748 

167 
1.47820 

Spec.    Rot.   Power  

+17.91 

+17.53 

+17.77 

17.15 

+16.83 

+8.99 

Flash  Point  C  

32 

32 

32 

38 

Distilling  under  165V&    .      .. 

88  50 

91  00 

85.00 

32.78 

Although  the  tests  here  given  do  not  prove  that 
this  oil  is  pinene,  the  production  of  a  solid  hydro- 
chloride  of  the  formula  Cio  His  H  Cl  may  be  con- 
sidered to  be  a  partial  proof,  and  this  has  been 
done.  Also  terpin  hydrate  has  been  made  from 
this  oil. 

The  preparation  of  pinennitroso  chloride  and 
pinennitrol  piperidin  from  this  oil,  as  well  as  oth- 
er compounds,  ought  to  be  as  confirmatory  a  test 
as  would  apply  to  pinene  from  gum  spirits. 

As  has. been  noticed  in  many  instances,  the  oil 
from  destructive  distillation  varies  greatly  from 
that  of  the  steam  process,  and  is  probably  due  to 
the  presence  of  rosin  spirit  and  wood  oil. 


turpentine  obtained  by  distilling  the  wood,  a  thick, 
slightly  yellow  oil  comes  over.  Although  the  oil 
is  well  known,  no  distinctive  name  is  given  to  it, 
nor  is  its  chemical  composition  known.  It  may  be 
the  intermediate  compound  between  turpentine  and 
rosin  and  consequently  be  found  to  contain  oxygen. 
It  might  be  supposed  that  this  compound  would  be 
pinole  hydrate, mixed  with  oily  matter,  this  pinole 

H 
hydrate  being  the  same  as  sobrerol  Cio  Hi8  O 

OH 

produced  by  exposing  oil  of  turpentine  to  the 
action  of  moist  oxygen  in  the  sunlight. 

However,   an   investigation   made   at   the   Massa- 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


127 


chusetts  Institute  of  Technology  seemed  to  indi- 
cate that  it  was  more  of  the  nature  of  turpineol. 
Turpineol  seems  to  be  an  alcohol  Cio  H]7  OH,  and 
several  different  compounds  go  by  that  name.  One 
form  boils  at  215  degrees  to  218  degrees  C.,  and 
if  it  contained  a  small  amount  of  turpentine  it 
might  be  expected  to  boil  at  a  lower  temperature. 
In  the  investigation  above  mentioned,  the  yellow 
.cil  was  submitted  to  a  fractional  distillation.  Al- 
most the  entire  amount  boiled  between  200  —  214 
degrees  C.  The  fraction  209  —  211  constituted  fully 
GO  per  cent  of  the  whole,  and  was  apparently  a 
homogeneous  substance.  When  the  oil  was  diluted 
with  alcohol,  saturated  with  dry  HC1  gas,  and 
cooled,  it  solidified  to  a  mass  of  'white  crystals, 
melting  at  50  degrees  C.  —  The  indications  are  that 
ii,  is  terpineol. 

Rosin. 

The  substance  left  after  distilling  the  turpentine 
oil  from  crude  gum  turpentine  is  called  rosin  or 
colophony.  This  substance  is  also  produced  by 
carefully  boiling  down  the  resin  drawn  from  heart-  ' 
wood  by  heat.  This  latter  is  not  as  good  as  the 
gum  rosin,  as  it  is  colored  too  deeply. 

Rosin  is  very  brittle,  melts  at  100  degrees  to  140 
degrees  C.,  and  has  a  specific  gravity  of  about  1.075. 
Alkalies  convert  it  into  a  deliquescent  and  soluble 
soap  called  "rosin  soap."  It  consists  of  abietic 
anhydride  and  abietic  acid.  Some  consider  it  a 
mixture  of  hydric  pinate  and  sylvate  and  consider 
that  rosin  may  be  an  oxidation  product  of  turpen- 
tine, as  follows: 

4Cio  H™  +   SO..  =  2Cso  Hso  D£  +  2H2  O 

Whether  the  oil  is  formed  from  the  rosin  or 
the  rosin  from  the  oil  is  not  definitely  known. 

The  oleo-resin  from  which  ordinary  rosin  is  pro- 
duced is  considered  by  Tschirch  &  Koritzschoner 
to  consist  of  the  following  ingredients: 


Palabienic  acid  C13  HZO  O2 
Palabietic  acid  CM   H30  O2 
A  and  B  Palabietiolic  acid  Ci8 
Spirits    of    turpentine 
Paloresene 


5% 

,  .     6% 
2  ..............  56% 

20% 
10% 
Impurities,    bitter   principles   and   water  ...........     3% 


Upon  distillation  only  the  oils  pass  over,  and 
it  would  be  expected  the  other  products  would  re- 
main behind  practically  unchanged.  It  doesn't 
seem  advisable  to  give  any  definite  composition  to 
pine  products  as  now  produced,  for  not  even  the 
turpentine  itself  is  of  stable  composition. 

The  distillation  of  the  gum  turpentine  is  per- 
formed in  copper  stills  heated  by  a  direct  fire,  hot 
water  being  added  to  the  still  from  time  to  time 
in  small  quantities.  Steam  would  probably  be  bet- 
ter. The  temperature  of  the  distillation  is  much 
reduced,  but  does  not  follow  exactly  the  laws  gov- 
erning the  distillation  of  two  immiscible  liquids. 
The  temperature  of  distillation  of  oil  of  turpentine 
with  steam  when  both  vapors  are  saturated  is  less 
than  100  degrees  C.  After  the  oil  is  removed,  the 
cap  is  taken  off  the  still  and  the  excess  water 
boiled  off  and  hot  rosin  run  off  through  a  cotton 
filter  into  a  trough,  from  which  it  is  dipped  into 
barrels. 

Rosin  is  stable  at  150  degrees  C.,  distillation  tak- 
ing place  at  a  higher  temperature  (250-300  degrees). 
Rosin  spirit  or  pinoline,  rosin  oil,  gas  and  coke  or 
pitch  are  the  products  of  decomposition.  When 
distilled  in  a  vacuo  or  by  means  of  superheated 
steam,  very  little  decomposition  takes  place.  Ros- 
in can  be  separated  from  mineral  oils  by  treating 
with  acetone;  the  rosin  being  soluble  and  the  min- 
eral oils  not. 

Rosin   Spirit. 

As  this  substance  is  to  be  found  in  oil  of  tur- 
pentine produced  by  destructive  distillation,  some 
of  its  properties  will  be  described  here. 

Rosin  spirit  is  a  very  complex  body  produced  by 
the  destructive  distillation  of  rosin.  It  boils  be- 
low 250  degrees  C.  (78  to  250  degrees),  and  resem- 
bles oil  of  turpentine,  for  which  it  is  sometimes 
substituted.  It  is  now  often  called  naphtha  and 
amounts  to  about  3  per  cent  of  the  rosin  charge. 
The  spirit  is  found  to  contain  a  mixture  of  hydro- 
carbons and  oxygenated  bodies. 

Professor  Mills  has  made  an  examination  of  rosin 
spirit.  He  states  that  "a  fraction  from  the  spirit 
boiling  pretty  constantly  at  154-156  degrees  had 


128 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


Cz 

^flP^ic 

^P         rec 

^  Dill 


the  sp.  gr.  .852  at  14.4  degrees  C.,  and  almost  ex- 
actly the  composition  of  turpinol  (Cio  H«)2  EL  O. 
The  turpinol  of  Wiggers  and  List  is  said  to  have 
the  sp,  gr.  .852  and  boil  at  168  degrees  C.  Their 
product  gives  a  crystalline  hydrochloride  CioHi82HCl, 
but  rosin  turpinol  does  not  appear  to  do  so,  and  is 
certainly  not  identical  with  ordinary  turpinol.  When 
rosin  turpinol  is  treated  with  strong  oil  of  vitriol, 
it  yields  a  liquid  having  the  odor  of  terebene. 
When  treated  with  bromide,  it  furnishes  an  oily 
product,  containing  from  31  to  43  per  cent  of  the 
reagent;  chlorine  is  similarly  taken  up  to  the  ex- 
tent of  50  per  cent;  hydric  chloride  to  the  extent 
of  18  to  19  per  cent.  Another  fraction,  boiling  at 
188  degrees  to  193  degrees  and  dried  over  sodium, 
agreed  in  composition  very  closely  with  turpentine, 
but  it  could  not  be  made  to  yield  a  solid  hydro- 
chloride." 

Renard  gives  a  list  of  light  hydrocarbons'  with 
low  boiling  point  that  are  to  be  found  in  rosin  spirit 
and  rosin  oil.  Rosin  spirit  is  water-white  in  color, 
smelling  of  terpene.  It  is  generally  heavier  than 
turpentine.  The  sp.  gr.  may  vary  from  0.852  to 
0.883  and  the  flash  point  from  96  degrees  to  102 
degrees  F.  in  closed  tester.  It  has  no  rotary 
power,  one  sample  showing  only  [a]  v '  =  +  0.2; 
the  refractive  index  of  same  sample  being  1.4780. 
It  should  not  contain  rosin  oil.  The  bromide  test 
is  184  to  213. 

Rosin  spirit  is  said  to  contain  pentine  C»  H8 
(b.  pt.  50  degrees),  isobutylaldehyde,  isobutyric,  ca- 
proic  and  other  fatty  acids,  methyl  alcohol  (50  gr. 
from  150  kilos.),  a  hydrocarbon  C»  Hi2  (b.  pt.  about 
160  degrees  C.),  a  homolog  of  benzene,  ordinary 
cymene  and  a  new  cymene  (metapropyltoluene), 
metaisobutyltoluene  (186-188  degrees),  parabutyl 
toluene,  dipentehe,  a  large  portion  of  a  heptine 
C;  Hi2  (103  to  104  degrees),  probably  methyl  propyl 
ene  CH3.  CH:  C:  CH.  Ca  H3.  This  liquid  is  char- 
cterized  by  giving  a  succession  of  colors  (yellow, 
red,  green,  deep  blue)  when  agitated  with  strong 
sulphuric  or  hydrochloric  acid.  In  presence  of  air 
and  water,  it  forms  a  gylcol  C?  Hw  (OH)2,  which 
crystallizes  with  one  molecule  of  water  in  long, 
slender  prisms,  seen  in  old  samples  of  resin  spirit. 


Rosin   Oil. 

This  oil  is  produced  by  the  destructive  distilla- 
tion of  rosin  and  comprises  the  bulk  of  the  distil- 
late. The  specific  gravity  of  rosin  oils  ranges  be- 
tween 0.975  and  0.995.  That  ordinarily  used  is  be- 
tween 0.982  and  0.988.  The  iodine  value  averages 
112  to  115.  B.  pt.,  300  to  400  degrees  C. 

As  much  as  4  to  10  per  cent  unaltered  rosin  often 
distills  over,  and  this  gives  an  acid  reaction  to  the 
oil  of  from  .05  per  cent  to  5  per  cent. 

Rosin  oils  are  soluble  in  ethyl  alcohol  and  also 
in  a  mixture  of  phenol  and  glycerine;  also  in 
phenol  alone,  but. not  in  glycerol.  Alcohol  with 
phenol  dissolves  it,  as  do  carbon  bisulphide  and 
turpentine.  A  mixture  of  equal  parts  of  phenol, 
alcohol  and  rosin  oils  forms  a  good  mixture. 

The  action  of  nitric  acid  on  rosin  oil  varies; 
some  grades  it  attacks  readily,  while  other 
grades  are  not  affected  unless  heated. 

Rosin  oil  is  not  truly  saponified  by  alkalies,  but 
unites  with  them  to  form  greasy  bodies.  A  mixture 
with  lime  solidifies  soon;  one  with  caustic  soda  in 
a  few  days,  and  with  caustic  potash  in  a  longer 
period.  A  formula  of  13Cio  Hie  Ca  (OH)2  is  ascribed 
to  the  commercial  "Rosin  grease." 

Renard  considers  that  about  80  per  cent  of  rosin 
oil  consists  of  diterebentyl  Cao  Hso  (b.  pt.  343-346 
degrees  C.),  10  per  cent  of  diterebentylene  €20  Has 
and  10  per  cent  of  didecene  C*)  Hsa  (b.  pt.  332  de- 
grees C.). 

Some  consider  that  rosin  consists  of  a  mixture 
of  abietic  acid  CM  HM  65  (m.  pt.  165  degrees  C)  and 
small  quantities  of  phenols,  with  a  mixture  of  hy- 
drocarbons (Cio  Hio)  n  (b.  pt.  above  360  degrees 
C.).  Rosin  oil  is  used  as  an  adulterant  for  olive 
and  boiled  linseed  oils  and  other  oils  and  a*,  w 
lubricant  on  iron  bearings. 

Wood  Oil. 

This  term  is  applied  to  the  first  oil  distilled  from 
tar  and  also  the  oil  dissolved  in  the  pyroligneous 
acid. 

Refined  wood  oil  is  the  oil  distilled  from  this 
crude  oil  by  means  of  steam.  There  are  a 
great  many  different  substances  found  in  the  crude 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


129 


oil,  a  list  of  which  has  been  already  given.  The 
wood  oil  from  hardwood  has  been  investigated  by 
G.  S.  Fraps  and  described  in  the  American  Chemi- 
cal Journal,  Vol.  25,  No.  1.  The  light  oil  from  fir 
wood,  which  would  resemble  pine  wood  oil,  has 
been  investigated  by  the  chemists  at  the  University 
of  Washington  at  Seattle.  This  can  be  found  in 
Journal  American  Chem.  Society,  Vol.  25,  Part  II., 
p.  7G4. 

The  wood  oil  will  vary  according  to  the  method 
of  production,  but  it  can  be  expected  to  contain 
tbe  light  rosin  oils  and  light  tar  oils.  The  inter- 
esting feature  to  the  distiller  is  that  an  oil  can  be 
produced  that  is  very  light  and  equal  in  quantity 
to  about  two-thirds  the  amount  of  the  turpentine 
produced.  This  oil  is  generally  yellow  and  turns 
darker  upon  exposure  to  the  air,  due  probably  to 
the  presence  of  a  tar  product.  The  oil  when  first 
distilled  from  the  tar,  contains  a  large  amount  of 
creosol  and  some  carbolic  acid,  both  of  which  can 
be  removed  with  soda.  This  oil,  when  oxidized  suf- 
ficiently to  destroy  the  coloring  matter  and  then 
redistilled,  can  be  made  almost  water  white  in  color. 

The  refined  oil  has  a  distinctive  odor,  is  a  pow- 
erful solvent,  a  quick  dryer,  and  can  be  used  for 
outside  painting.  It  is  often  used  as  a  creosote 
paint  when  mixed  with  suitable  pigments.  In  this 
case  it  is  better  not  to  remove  the  creosols  and 
phenols.' 

It  has  a  different  composition  from  oil  of  tar 
produced  by  destructive  distillation  of  the  tar,  but 
it  contains  some  oil  of  tar,  that  is  formed  by  the 
decomposition  of  the  tar  in  the  retort  while  the 
v/ood  is  distilling. 

Tar. 

Tar  obtained  by  destructive  distillation  of  pine 
wood  in  closed  vessels  seems  to  be  somewhat  dif- 
ferent from  the  pine  tar  coming  from  a  tar  kiln. 
There  are  several  reasons  to  be  ascribed  for  this; 
one  is  that  the  turpentine  is  removed,  another  that 
the  tar  itself  is  decomposed  into  lighter  oils  and 
depositing  coke,  and  another  reason  is  that  the  tan- 
nin in  the  wood  acts  on  the  iron  of  the  retorts  and 
stills  and  causes  a  dark  color. 


In  making  kiln  tar  only  extremely  fat  wood  is 
used,  while  in  retorts  a  poorer  quality  is  often 
used.  Lean  woods  give  dark  tars,  sawdust  tar 
being  nearly  black. 

The  following  comparison  between  fir  tar  from 
a  retort  and  Stockholm  and  pine  tar  is  given  be- 
low: 

Fir  Tar.  Stockholm.         Pine  Tar. 

Color.  Black  almost.     Brownish  black.     Brown. 

Smoky  but 

Odor.  Characteristic.  Smoky.  Resinous. 

Consistency.  Syrupy.  Syrupy.  Syrupy. 

Specific    gravity 1.10  1.09  1.11 

Per  cent.  Per  cent.  Per  cent. 

Light  oil    3  3  3 

Creosote    oil 34  30  40 

Pyroligneous   acid..   45  2 

Pitch    59  62  53 

Hardness 

of  Pitch.  Brittle.  Less  Brittle.  Soft. 

Color  of  Pitch.       Black.  Black.  Brown. 

Light  oil   sp.   gr.   0.945. 
Color.  Amber. 

Norwegian  tar,  according  to  Knut  Strom,  has 
the  following  characteristics:  Strongly  acid,  sol- 
uble in  alcohol,  acetic  acid,  ether  chloroform,  and 
benzene.  Sp.  gr.  at  15  degrees  C.,  1.068.  Compo- 
sition 4.78  per  cent  volatile  acids  (as  acetic  acids), 
11  per  cent  phenols  and  61  per  cent  hydrocarbons. 
Volatile  acids  (85  to  90  per  cent)  formic  and  ace- 
'tic;  proprionic  acid,  normal  butyric  acid,  normal 
valeric  acid,  (the  normal  valeric  acid  discovered 
by  Renard  in  pine  resin  M.  pt.  175.5  degrees  C.), 
methyl  propylacetic  acid,  normal  caproic  acid, 
oenanthylic  acid  and  normal  caprylic  acid.  No  un- 
saturated  acids  discovered.  Of  the  phenols,  were 
found  phenol,  guaiacol,  cresol,  creosol,  ethylguaia- 
col  and  two  phenols  Cu  Hw  Oa  —  Ci2  Hu  Oa,  respec- 
tively. Of  the  hydrocarbons  about  14  per  cent 
solid  (containing  retene  Cis  His),  and  86  per  cent 
liquids.  J.  So.  Chem.  Ind.,  1900. 

The    specifications    required    for    good    pine    tar 

are  given  below: 

Deg.  C.  Per  ct. 

Distilling    under 150  9.70 

Distilling  between   150  350  42.61 

Distilling  between   350-363  26.62 

Coke    .  21.07 


130 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


Some  of  the  products  of  distillation  of  different 
tars  will  be  found  in  Chapter  XII. 

Pitch. 

There  are  several  kinds  of  pitch  coming  from 
different  sources,  such  as  coal  tar,  wood  tar  and 
rosin  pitch. 

Stockholm  pitch  is  made  from  pine  wood  tar 
either  by  boiling  it  down  or  by  destructively  dis- 
tilling it.  This  pitch  is  brilliant  black,  having  a 
conchoidal  fracture,  but  brittle,  crumbling  between 
the  fingers.  Its  specific  gravity  is  1.105  and  melt- 
ing point  82  degrees  C.  It  is  slightly  adhesive, 
and  becomes  sticky  on  warming;  at  40  degrees  C. 
it  twists  easily.  When  heated,  88  to  88%  per  cent 
volatilizes,  leaving  a  soft,  friable  coke  containing 
.7  to  .84  per  cent  ash.  The  odor  when  boiling  down 
is  very  distinctive. 

Benzol  dissolves  it,  and  also  pyridine  bases.  Pe- 
troleum spirit  dissolves  only  91  to  92  per  cent. 
Sulphur  present,  only  .01  per  cent.  The  solution 
in  petroleum  shows  no  bloom  or  fluorescence,  the 
spectroscope  cuts  out  only  the  violet  spectrum,  no 
bands  visible,  nor  is  there  any  indication  of  chry- 
sene  said  to  exist  in  this  particular  tar  or  pitch. 

This  pitch  dissolves  almost  completely  in  alco- 
holic potash.  This  neutralized  and  boiled  yields 
volatile  fatty  acids.  (Thorpe's  Diet,  of  Applied 
Chem.). 

Pyroligneous   Acid. 

This  acid  comprises  chiefly  acetic  acid,  wood 
alcohol,  acetone  and  dissolved  oils.  Other  prod- 
ucts are  found  and  are  contained  in  the  list  pre- 
viously given.  The  amount  of  acetic  acid  from 
pine  wood  is  equal  to  about  2.5  to  5.5  per  cent  of 
the  weight  of  the  pyroligneous  acid. 

Acetic  Acid    C2  H4  Os  =  C  H3  C  O2  H. 

This  acid  is  produced  chiefly  from  table  vine- 
gar made  from  alcohol  and  from  wood  vinegar  or 
pyroligneous  acid.  It  is  also  a  product  of  the 
decomposition  of  cellulose  by  alkalies  and  acids. 

The  strongest  acetic  acid  is  known  as  "glacial 
acetic"  acid,  from  its  crystallizing  in  icy  leaflets 
at  about  40  degrees  F.  Above  CO-  degrees  the 


crystals  fuse  to  a  thin,  colorless  liquid  of  an   ex- 
ceedingly  pungent  and   well-known  odor. 

The  gravity  of  pure  acetic  acid  is  given  as  1.055 
to  LOGO  at  59  degrees  F.  The  sp.  gr.  of  a  solution 
of  acetic  acid  in  water  is  no  indication  of  the 
amount  of  acid.  Common  acetic  acid  of  commerce 
is  a  slightly  colored  liquid  of  about  1.04  sp.  gr., 
and  containing  appromixately  30  per  cent  anhyd- 
rous acid. 

The  boiling  point  of  pure  acetic  is  118  degrees 
C.  It  gives  off  a  vapor  which  burns  with  a  flame 
like  alcohol. 

The  action  of  heat  is  interesting,  as  it  is  some- 
times affected  in  a  hot  retort.  When  its  vapor 
is  passed  through  a  red-hot  tube,  it  yields  several 
products,  among  which  marsh  gas  and  acetone  are 
conspicuous.  This  action  is  much  more  marked 
in  the  presence  of  glowing  carbon.  Acetic  acid  is 
very  corroding.  It  strongly  attacks  iron;  wrought 
iron  is  eaten  out  very  quickly  and  cast  iron  be- 
comes so  soft  that  it  can  be  whittled  with  a  knife. 
It  has  been  found  that  real  hot  vapors  affect 
wrought  iron  less  than  colder  ones,  hence  we  find 
that  the  hottest  parts  of  a  retort  are  made  of 
wrought  iron,  while  the  connecting  pipes  and  cooler 
parts  of  the  retort,  such  as  the  head,  are  made 
of  cast  iron.  Acetic  acid  attacks  copper  slowly 
to  form  acetate  or  verdigris. 

Acetic  acid  is  the  strongest  organic  acid  and  is 
not  easily  oxidized.  With  alkalies  and  metallic 
bases  it  forms  acetates  which  will  not  be  de- 
scribed, except  calcium  acetate. 

Commercial  acetic  acid  is  prepared  from  gray 
or  brown  acetate  of  lime  by  distilling  with  con- 
centrated hydrochloric  acid  in  copper  stills,  care 
being  taken  to  have  an  excess  of  lime  salt  in  the 
still.  The  acid  formed  is  colored  and  contains 
about  50  per  cent  anhydrous  acid.  With  dilute 
acid  in  the  still,  the  acid  is  purer  and  contains 
only  30  per  cent  anhydrous  acid.  Often  the  acid 
is  distilled  in  Marx  vessels  and  filtered  in  towers 
through  freshly  burned  charcoal. 

Wood  Alcohol  C  H,  O  =  C  H3  O  H. 

This  substance  in  a  pure  state  is  a  colorless, 
mobile  liquid,  known  as  Columbian  and  Colonial 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


131 


spirits.  It  boils  at  149  degrees  Fah.  It  is  very  in- 
flammable, burning  with  a  pale  flame.  The  pure 
alcohol  is  difficult  to  distinguish  from  grain  or 
ethyl  alcohol,  as  the  odor  and  color  are  alike. 
Methyl  and  ethyl  alcohol  can  be  distinguished  from 
each  other  by  distilling  them  with  dilute  sulphuric 
acid  and  potassium  dichromate,  when  the  former 
yields  formic  acid  and  the  latter  acetic  acid.  The 
formic  acid  produced  may  be  distinguished  from 
the  acetic  acid  by  its  property  of  reducing  silver 
ammonio-nitrate  to  the  metallic  state  when 
warmed  with  it. 

Methyl  alcohol  forms  a  crystalline  compound 
with  calcium  chloride  (C'a  C12)  the  formula  being 
Ca  Cb  (C  Hi  O>4.  This  compound  is  stable  at 
100  degrees  C.,  so  by  heating  to  100  degrees  C. 
the  acetone  and  methyl  acetate  distill  over  from 
crude  wood  spirit,  leaving  this  compound.  By 
adding  an  equal  weight  of  hot  water  this  compound 
is  decomposed,  and  by  continuing  the  distillation, 
pure  methyl  alcohol  distills  over,  accompanied  by 
some  water,  which  can  be  removed  by  contact  with 
quicklime  and  distillation.  It  can  also  be  obtained 
pure  from  wood  spirit  by  heating  with  anhydrous 
oxalic  acid  in  a  flask  connected  with  an  inverted 
condenser,  until  the  methyl  alcohol  is  converted 
into  methyl  oxalate  (C  O.  O  C  H3)2)  which  sep- 
arates in  crystals  on  cooling.  The  crystals  are  col- 
lected, washed  with  water  and  distilled  with  potash. 

Commercial  methyl  alcohol  is  often  slightly  yel- 
lowish in  color  and  has  a  disagreeable  odor.  It 
is  largely  used  as  a  solvent  in  varnish  making,  the 
acetone  contained  therein  being  an  advantage. 
The  turbidity  noticed  when  crude  wood  spirit  is 
mixed  with  water  is  due  to  the  separation  of  hy- 
drocarbons, which  were  contained  in  the  alcohol. 

Wood  alcohol  is  used  for  the  preparation  of 
methylated  spirit  or,  as  it  is  called,  "denatured"  al- 
cohol, which  is  a  mixture  of  grain  alcohol  with  a 
small  percentage  of  wood  alcohol  or  other  denatur- 
izing  agent. 

Its  production  in  the  United  States  will  prob- 
ably be  somewhat  curtailed  on  account  of  the  lack 
of  demand,  due  to  the  use  of  "denatured"  alcohol 
in  its  stead. 


Acetone. 

Acetone  is  found  in  wood  spirit.  It  boils  at 
56.3  degrees  C.,  and  hence  cannot  well  be  removed 
from  the  alcohol  by  distillation  over  lime.  To  re- 
move it,  the  alcohol  is  fixed  by  the  calcium  chlor- 
ide, as  described  under  wood  alcohol,  and  the 
mixture  distilled  under  100  degrees  C.  until  the 
acetone  is  driven  out. 

Regnault  and  Villejean  dissolve  in  the  wood 
spirit,  previously  purified  as  much  as  possible,  10 
per  cent  of  its  weight  of  iodine,  add  concentrated 
solution  of  potassium  hydroxide  in  small  portions 
until  decoloration  is  complete,  and  distill  the  mix- 
ture at  a  very  moderate  heat.  The  iodine  and 
caustic  unite  with  the  acetone  to  form  iodoform. 
Sometimes  the  alcohol  is  treated  with  chlorine  and 
chlor-acetones  are  formed  showing  high  boiling 
points  and  from  which  the  alcohol  is  separated 
by  distillation. 

On  a  commercial  scale,  acetone  is  .made  by  the 
dry  distillation  of  gray  acetate  of  lime  at  290  de- 
grees C.  in  retorts  which  are  connected  with  a 
cooling  apparatus.  In  Chute's  process  the  pulveru- 
lent material  is  continuously  conveyed  in  a  thin 
film  or  layer  over  a  heated  surface  maintained  at 
the  proper  temperature,  and  the  acetone  is  re- 
moved by  a  current  of  oxygen-free  gas  moving  in 
an  opposite  direction,  under  a  partial  vacuum,  the 
gas  being  reheated  and  reused. 

A  commercial  method  for  the  production  of  ace- 
tone devised  by  Dr.  E.  R.  Squib  consists  of  pass- 
ing acetic  acid  vapor  through  a  rotating  iron  cylin- 
der, heated  to  about  500-600  degrees  C.,  and  con- 
taining pumice  stone  with  precipitated  barium 
carbonate.  On  leaving  the  still  the  vapors  pass 
through  a  fractional  condensation  apparatus,  to 
remove  water  and  acetic  acid;  the  dilute  acetone 
condenses  in  a  second  condenser.  The  barium  car- 
bonate acts  merely  as  a  contact  body,  since  the 
temperature  is  always  above  that  at  which  barium 
acetate  decomposes. 

Acetone  produced  from  acetate  of  lime  by  distil- 
lation is  impure  and  needs  refining.  Sodium  bisul- 
phite is  added  to  form  a  double  salt  with  the 
acetone,  which  is  readily  purified  by  crystallization 


132 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


from  aqueous  solution.  By  heating  this  salt  with 
sodium  carbonate  solution,  acetone  is  set  free  and 
may  be  distilled  off  in  a  pure  state.  The  water  is 
removed  by  fused  calcium  chloride. 

This  action  of  sodium  bisulphite  can  be  utilized 
to  remove  acetone  or  other  ketones  from  wood 
oils.  When  acetone  loses  the  elements  of  water 
by  the  action  of  dehydrating  agents  such  as 
Hr  S  O4  HC1  and  Ca  O,  condensation  products  are 
formed,  such  as  mesityl  oxide,  a  liquid  smelling  of 
peppermint  and  boiling  at  130  degrees  C.  (2(CH3)2 
CO  —  H2O),  phorone  and  mesitylene,  all  of  which 
are  found  in  the  products  of  distillation  of  pine 
wood. 

The  sp.  gr.  of  acetone  is  0.80.  It  is  inflammable, 
burning  with  a  luminous  flame.  It  mixes  with 
water,  alcohol  and  ether.  When  oxidized  it  yields 
acetic  acid  and  carbon  dioxide. 

Acetone  can  be  separated  from  a  comparatively 
strong  aqueous  solution  by  adding  concentrated 
calcium  chloride.  The  acetone  will  rise  to  the 
top. 

Calcium   Acetate. 

This  substance  is  found  in  trade  as  the  gray  and 
brown  acetate  of  lime.  There  is  also,  of  course,  a 
chemically  pure  salt. 

The  difference  lies  in  the  amount  of  tarry  mat- 
ter contained  therein.  Generally  the  yield  of 
brown  acetate  of  lime  is  one-third  greater  than 
that  of  the  gray,  but,  of  course,  it  means  more  im- 
purities rather  than  more  acetic  acid. 

To  make  acetate  all  the  waste  heat  is  utilized 
as  far  as  possible,  some  plants  even  putting  their 
acetate  pans  on  top  of  the  retorts. 

It  is  cheaper  to  make  brown  acetate  of  lime,  as 
it  takes  less  fuel.  This  form  of  acetate  is  made 
by  directly  neutralizing  the  pyroligneous  acid  with 
lime  and  then  distilling  off  the  alcohol.  The  resi- 
dual liquor  is  then  evaporated  to  dryness  and  par- 
tially charred  to  destroy  tarry  matters.  The  gray 
acetate  is  made  by  distilling  the  pyroligneous  acid 
to  remove  both  the  acetic  acid  and  alcohol.  The 
acetic  acid  vapor  is  passed  through  lime  before 


it  reaches  the  condenser,  thus  fixing  it,  while  the 
alcohol  vapor  passes  on  and  is  condensed. 

Brown  acetate  is  made  at  some  plants  from  the 
pyroligneous  acid  obtained  from  pine  wood  by  sim- 
ply evaporating  without  the  recovery  of  the  alco- 
hol. This  product  does  not  give  as  much  satis- 
faction as  the  hardwood  variety. 

As  stated  under  destructive  distillation  methods, 
acetate  is  made  by  neutralizing  the  settled  pyrolig- 
neous acid  exactly  with  lime  or  limestone  and 
filter-pressing  to  remove  tarry  products  and  im- 
purities in  the  lime,  etc.  The  fluid  is  then  acidu- 
lated with  crude  hydrochloric  acid  and  allowed  to 
rest,  whereby  a  deposit  is  formed.  The  clear 
liquor  is  drawn  off  and  evaporated  in  copper  pans 
heated  by  steam  and  provided  with  a  set  of  stir- 
rtrs  to  prevent  the  acetate  from  burning  to  the 
bottom.  The  tarry  matter  rising  to  the  surface  is 
removed  through  a  sliding  door.  When  the  sp.  gr. 
(measured  hot)  reaches  1.116,  the  separation  of 
acetate  begins,  and  gradually  the  mass  forms  a 
thick  paste  which  is  removed  and  spread  on  flat 
iron  pans  to  be  dried.  During  this  last  operation, 
the  material  should  be  constantly  stirred  with  iron 
shovels.  Some  finish  the  drying  in  rooms  heated 
with  waste  furnace  or  retort  gas. 

Sometimes  gray  acetate  is  made  by  distilling  the 
alcohol  and  then  after  changing  the  receiver  the 
acetic  acid  is  distilled  over  and  afterwards  neu- 
tralized with  lime  and  evaporated  in  the  usual 
manner. 

In  the  North,  the  acetic  acid  and  alcohol  are  re- 
moved by  distillation,  the  tar  remaining  in  the 
still.  The  distillate  goes  to  another  still,  where 
lime  is  added  and  the  alcohol  distilled  off.  The 
acetate  in  the  still  is  removed  and  evaporated  in 
the  usual  manner,  forming  gray  acetate. 

Charcoal. 

The  residue  in  the  retort  left  after  distilling 
wood  is  charcoal,  and  it  is  very  important  that 
it  contains  but  little  tar,  as  this  will  cause  it  to 
smoke. 

The  amount  of  carbon  in  charcoal  produced  at 
various  temperatures  is  shown  as  follows: 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


133 


Temperature  of  carbonization. 

Cent.  Fahr. 

150  302 

200  392 

250  482 

300  592 

350  662 

432  810 

1023  1873 


Carbon  per  cent 
47.51 
51.82 
65.59 
73.24 
76.64 
81.64 
81.97 


It  will  be  noticed  that  there  is  little  to  be  gained 
by  heating  above  810  degrees  Fan. 

Charcoal  exposed  to  the  air  absorbs  moisture  in 
variable  quantity,  according  to  the  temperature  at 
which  it  was  burned.  Thus,  at  150  degrees  it  ab- 
sorbs 21  per  cent  of  its  weight;  at  250  degrees,  7 
per  cent;  at  350  degrees,  6  per  cent;  at  450  de- 
grees, 4  per  cent,  and  at  about  1500  degrees  C., 
about  2  per  cent. 

The  kindling  temperature  in  the  open  air  is 
higher  where  the  heat  has  been  greater.  Thus 
coals  burned  at  260  degrees  to  280  degrees  take 
fire  at  340  degrees  to  360  dgrees  C.;  those  burned 
at  290  degrees  to  350  degrees  take  fire  at  360  de- 
grees to  370  degrees;  those  at  400  degrees  kindle 
at  400  degrees,  and  those  at  1000  to  1500  degrees, 
at  600  degrees  to  800  degrees,  and  these  latter 
burn  with  difficulty. 


Charcoal  has  great  powers  of  absorption.  It  will 
absorb  coloring  matter  from  liquids  and  also  ab- 
sorb large  quantities  of  gases,  those  gases  that  are 
most  soluble  in  water  being  the  most  absorbed. 
This  property  is  much  more  marked  when  recently 
charred  and  the  air  excluded. 

In  a  box  or  case  containing  one  cubic  foot  of 
charcoal  may  be  stored  a  little  over  nine  cubic 
feet  of  oxygen,  representing  a  mechanical  pressure 
of  126  pounds  to  the  square  inch.  From  the  store 
thus  preserved,  the  oxygen  can  be  drawn  by  a 
small  hand  pump. 

The  composition  of  charcoal  made  at  the  same 
temperature  varies  with  the  different  woods.  One 
species  of  wood  burned  at  various  temperatures 
gave  the  following: 


Temperature 

of  charring. 

Carbon. 

Hydrogen. 

Oxygen. 

Ash. 

270   Deg.    C. 

71.0 

4.60 

23.00 

1.40 

363 

80.1 

3.71 

14.55 

1.64 

476 

85.8 

3.13 

9.47 

1.60 

519 

86.2 

3.11 

9.11 

1.58 

The  specific  heat  of  charcoal  at  different  temper- 
atures is  given  below: 


0-23  Deg.  C. 
.1653 


0-90  Deg. 
.1935 


0-223   Deg. 
.2385 


CHAPTER  XL 

YIELDS  AND  DISPOSALS  OF  PRODUCTS. 


The  question  arises,  what  is  the  yield  of  differ-  From  dry  distillation  of  the  wood: 

ent  products  per  cord  of  wood  when  distilled?'   It  Grey  acetate  of  lime 46.2  ibs. 

is  quite  apparent  that  the  amount  of  different  prod-  Light  oil  18.4  gals.  2.34 

ucts  will   vary  greatly,   according  to  the  different  Charcoal    1050  ibs.  17.50 

conditions.       The   unit   is   generally  .the   cord,   al-  Gas    3750  cu.  ft.  (?)     2.00 

Wood  tar   1217  Ibs.  20.23 

though   the    amounts    and   percentages    are    some- 
times  given  by  weight.  From    distillation    of    rosin: 

A  cord  of  wood  means  128  cu.  ft..,  feut  it  never  Rosin  spirit   2.5  gals.  0.3 

amounts  to  that  much;  knots,  crooked  sticks,  short  Rosin    oil    10.9  gals.  1.5 

ends,  etc., 'all  cause  the  actual  quantity  to  be  less.  Blue  o11  7-25  sals.  i.o 

Green    oil    5.6  gals.  0.8 

The    amounts    should    be    determined    by    weights, 

Pitch   12  Ibs.  0.2 

and  even  then  differences  occur  on  account  of  the 

varying  content  of  water.  From   distillation   of   wood   tar: 

The  actual  per  cent  of  wood  as  given  by  Marcus 

Creosote  oil   (lo  per  cent) »...      306  Ibs.  5.1 

Bull,  is  56   per  cent  solid   wood  and  44   per  cent  wood   pitch  516  ibs.  8.6 

interstitial   spaces. 

From  creosote  oil: 
The  official  determination  in   Prussia,  according 

to  B.  E.  Fernow,  is:  Creosote     45.9  Ibs.  0.76 

Specific   gravity   of   the   woo'd,    1.075. 

Firewood  cords.      Billet  cords. 

A  test  on   600  Ibs.  of  dry   light  wood  gave  the 
Timber  cords,     (over  6"  diam.)   (over  3"  diam.) 

Cu.   ft 80  75  60  following: 

Pounds. 

Brushwoods  Spirits   of  turpentine    21% 

(less  than  3"  diam.)          Roots.  Pyroligneous  acid    95 

Cu.    ft 23.70  47.36  Heavy  oils  and   tar    150 

Charcoal    127 

The  amount  of  turpentine  in  the  pine   may  be  Water  and  gas  206% 

stated  to  vary  from  0.27  to  3.50  per  cent  of  the  Total 

weight  of  the  wood. 

A  complete  test  of  light  wood  estimated  at  6,000  This  is  suPP°sed  to  equal  a  yield  by  the  cord  of 

Ibs.  to  the  cord   was  made  at  the   Massachusetts  24    gallons    sPirits    of    turpentine,    88    gallons    of 

Institute  of  Technology,  with  the  following  results.  Pyroligneous   acid,   120    gallons   tarry   and   heavier 

The  turpentine  was    taken  off  with   steam   at  40  oily  Products  and  56  bushels  of  charcoal. 

Ibs.   pressure,   and   the   residue    destructively   dis-  One  of  the  earlier  plants  gives  the  following  from 

tilled:  a  cord:    Spirits   of  turpentine  5   to  18  gallons,   of 

From  steam  distillation:  heavier  oils  and  tarry  products  known  as  dead  oil 

or  creosote  from  60  to  100  gallons,  and  of  stronger 

acid   (of  a  specific  gravity  1.02)   60   gallons,  or  of 
Product.  Amount.          per  cent. 

Turpentine    24.9  gals.  3.00  W6aker    aCid    12°    gall°nS' 

Yellow  oil   4.4  gals.  0.56  ^n  analysis   given   by   Prof.   Cox   is   as   follows: 

Rosin    318  Ibs.  5.30  First  quality,  turpentine,   16  gallons;   second  qual- 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


135 


ity,  turpentine,  10  gallons;  alcohol,  6  gallons;  ace- 
tate of  lime,  ICO  Ibs.;  tar,  1  barrel. 

Another  from  a  card  weighing  5,000  pounds,  8% 
tc  9  gallons  turpentine,  a  barrel  to  a  barrel  and  a 
quarter  of  tar,  about  a  gallon  and  a  half  of  al- 
cohol and  atout  170  gallons  pyroligneous  acid. 

Another  more  detaileu,  the  results  of  investiga- 
tions made  by  Mr.  J.  D.  Lacey,  of  New  Orleans: 

Turpentine 22  gals. 

Pine    Tar    75  gals. 

Wood    alcohol    2  gals. 

Lime   acetate    40  Ibs. 

Charcoal    48  bu. 

Another: 

Russian   turpentine    16  gals. 

Rosin  oil   42  gals.,  kidney. 

Rosin    oil    8  gals.,  heavy. 

Creosote     10  gals. 

Wood   alcohol    4  gals. 

Acetate    of    lime 100  Ibs. 

Charcoal    500  Ibs. 

No  one  has  experimented  with  wood  of  varying 
fatness,  using  large  quantities. 

The  author  made  a  test  on  some  long  leaf  yellow 
pine  cut  into  short  lengths.  These  short  lengths, 
after  cording  carefully,  measured  2.36  cords  and 
weighed  8.G14  Ibs.,  or  about  3,647  Ibs.  per  cord. 

The  yield  per  cord,  air  dry,  was  as  follows: 

Weight,  Ibs.  % 

Clear  white  turpentine..  18.64  gals.  134.20  3.679 

Wood    oil    11.09  gals.  86.50  2.371 

Tar     96.       gals.  846.72  23.216 

Acid     95.9     gals.  830.49  22.771 

Coke    14.74  .404 

Charcoal     796.00  21.826 

Yellow  oil   and   pitch 6.78  gals.  57.02  1.563 

Gas   and   loss...  881.33  24.16G 


Total     3647.00  99.996 

The  turpentine,  after  distilling,  was  a  clear 
white  oil,  testing  as  follows:  Sp.  gr.  at  20  degrees 
C.,  0.8654-B.  Pt.  156.5  degrees  C.  Index  of  refrac- 
tion, 1.47210,  sp.  rot.  power  plus  17.91  at  20  de- 
grees C.,  flash  point  32  degrees  C.  (closed  tester). 

The  turpentine  was  taken  off  by  means  of  super- 
heated steam  under  a  pressure  of  only  a  few 
ounces,  then  redistilled,  yielding  the  above 


quantity  of  oil.  The  residue  was  then  destructive- 
ly distilled  and  the  wood  oil  steamed  from  the 
tar.  •  The  wood  oil  contained  no  turpentine,  but 
did  contain  large  quantities  of  rosin  oil  and  creo- 
sote oil. 

In  Minnesota,  with  Norway  pines,  the  yields  are 
said  to  be: 

Turpentine     16  gals. 

Tar     30  gals. 

Charcoal    30  bu. 

On  the  Pacific  coast,  with  fir,  the  yields  are 
about  the  same  as  in  Minnesota  on  the  same  class 
of  wood. 

With  sawdust  the  yield  varies  with  the  amount 
of  rosin  in  the  wood,  from  y2  gallon  to  5  gallons 
per  ton,  air  dry.  With  fat  slabs  the  yield  would 
be  about  24  gallons,  or  less,  according  to  rich- 
ness. 

The  yield  depends  entirely  upon  the  resin,  as 
nearly  all  processes  will  extract  the  oils  if  given 
t!me  and  heat  enough.  In  destructive  distillation 
processes  it  can  be  readily  understood  that  too 
rapid  heating  causes  more  gas  at  the  expense  of 
the  other  products. 

In  the  hardwood  industry  one  plant  using  70 
per  cent,  maple  averaged  per  cord  as  follows  dur- 
ing the  year  1906,  from  wood  four  foot  long: 

Wood   alcohol 11.32  gals.,  82% 

Acetate  of  lime 172.56  Ibs. 

Charcoal    54.18  bu. 

In  the  United  States,  by  weight,  for  hardwood, 
the  following  are  given  as  the  average  results 
in  per  cent: 

Wood    alcohol    1.434 

Acetate  of  lime 6.250     82% 

Charcoal     -31.2 

In  Germany  the  results  from  a  cord  of  pine  are 
as;  follows: 

Turpentine     12.25  gals. 

Brown    acetate     88.82  Ibs. 

Tar    '• 40.4     gals. 

Wood    alcohol    8.!% 4.1     gals. 

Charcoal     808.0    Ibs. 

The  following  table  of  yields  is  given  by  the 
Bureau  of  Chemistry  and  gives  an  idea  of  the 
variableness  of  the  yields  from  different  woods. 


136 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


AMOUNT   OF  PRODUCTS   YIELDED    PER 
Alcohol 
(crude) 

CORD   OF   WOOD. 

containing     Acetate 

Turpen- 

Classes of  woods. 

Charcoal. 

acetone. 

of  lime. 

Tar. 

Wood  oils. 

tine. 

Gas. 

Bushels. 

Gallons, 

Pounds. 

Gallons. 

Gallons. 

Gallons. 

40  to  50 

8  to  12 

150  to  200 

8  to  20 

Resinous  woo'ds   

25  to  40 

2  to    4 

50  to  300 

30  to  60 

30  to  60 

o!2  to  25 

b2  to  10 

Sawdust    (hardwood)    . 

.  .   25  to  35 

2  to    4 

45  to    75 

a  Lightwood. 


b  Sawdust. 


With  pine,  the  yield  in  turpentine  by  steam  dis- 
tillation is,  with  ordinary  pine  2  to  5  gallons  per 
cord,  while  good  light  wood  yields  from  10  to  20 
gallons  and  averages  about  15  gallons  per  cord, 
and  very  rich  light  wood  from  20  to  30  gallons  per 
cord. 

Unfortunately,  the  greater  amount  of  the  available 
pine  is  of  the  low  yielding  variety  and  the  supply 
of  good  light  wood  at  most  plants  is  soon  ex- 
hausted, thus  causing  failure. 


RESULTS   FROM   DIFFERENT   METHODS 
CHARCOAL  MAKING. 


OF 


*    £< 

',•*     ft 


°-0 
I*  <D         <D 

P         1^ 
oj  31      -2  «) 
h  'O       O  o 

28    >  ^ 
*  2     c  ® 
u  >    M  a 

In  weight 
per  cent. 

Bushels  of  < 
coal  per  cor 

Weight  in  11 
bushel  of  cl 

periments:    birch 

35.9 

rt 
O 
U 

Odelstjerna's    ex 
dried  at  230  F 

Mathieu's  retorts,  fuel  excluded, 
(air  dried,  average  good  yel- 
low pine,  weighing  about  28  Ibs. 
per  cu.  ft.) 77  28.3  63.4  15.7 

Mathieu's  retorts,  fuel  included, 
(air  dried,  average  good  yel- 
low pine,  weighing  about  28  Ibs. 
per  cu.  ft.) 65.8  24.2  54.2  15.7 

Swedish    ovens,    average    results, 

(good 'dry  fir  and  pine  mixed).  .81.0       27.7       66.7       13.3 

Swedish  ovens,  average  results, 
(poor  wood  mixed  fir  and  pine).. 70.0  25.8  62  13.3 

Swedish  meilers,  exceptional  (fir 
and  white  pine  wood  mixed, 
average  25  Ibs.  per  cu.  ft.) 72.2  24.7  59.5  13.3 

Swedish  meilers,  average  results. 52. 5       18.3       43.9       13.3 

American  kilns,  average  results, 
(average  good  yellow  pine 
weighing  about  25  Ibs.  per  cu. 
ft.)  54.7  22.0  45  17.5 

American  meilers,  average  re- 
sults, (average  good  yellow 
pine,  weighing  about  25  Ibs. 
per  cu.  ft.) 42.9  17.1  35  17.5 


DISPOSAL   OF   THE    PRODUCTS. 

With  the  demand  for  turpentine  increasing  at  a 
rapid  rate,  it  would  seem  an  easy  proposition  to 
dispose  of  some  of  the  products  of  distillation. 
However,  the  prejudice  against  wood  turpentine  and 
retort  tar  is  still  very  great. 

Turpentine. — Turpentine  ought  to  be  sold  as 
such  upon  its  merits.  It  is  necessary  to  make  a 
refined  article  of  stable  quality  in  order  to  com- 
mand a  ready  sale,  even  at  a  less  price  than  the 
market  price  of  orchard  turpentine. 

Any  surplus  might  be  disposed  of  by  converting 
into  turpentine  derivatives,  such  as  terpine 
hydrate,  terpineol  (used  for  making  lilac  perfume), 
camphor,  artificial  camphor  and  similar  com- 
pounds. 

Yellow  Oil. — This  compound,  if  it  proves  to  be 
terpineol,  may  be  changed  into  numerous  bodies. 
In  the  present  state  of  knowledge  regarding  this 
product  it  may  be  used  in  combination  with  caus- 
tic as  a  disinfectant,  for  stack  paint  or  for  mix- 
ing with  the  residue  for  kindling. 

Wood  Oil. — The  refined  wood  oil  can  be  mixed 
with  suitable  colors  to  form  shingle  stains.  The 
crude  wood  oil  can  be  used  for  dark  colored  shin- 
gie  stains  and  for  creosote  paints. 

The  pyroligneous  acid  is  sometimes  used  as  a 
sheep  dip,  disinfectant,  spray  on  trees,  etc.  It 
can  be  converted  into  acetate  of  lime  and  black 
liquor  (iron  acetate),  which  latter  is  used  as  a 
mordant  for  dyeing,  and  can  also  be  used  for  a 
black  stain  on  wood. 

Tar  oil,  the  name  applied  to  the  crude  tar  and 
oil  coming  from  the  retort,  is  used  in  various 
ways,  as  for  soap,  etc.,  also  for  creosoting  lumber. 


THE    UTILIZATION    OP    WOOD    WASTE    BY    DISTILLATION. 


137 


Tar. — This  is  generally  sold  as  such,  but  may 
be  regularly  distilled  to  produce  oil  of  tar,  creo- 
sote oil  and  pitch.  Black  tar  and  pitch  might  be 
used  in  road-making  and  for  making  products 
where  coal  tar  is  now  used. 

Rosin  and  Resin. — These  are  best  sold  as  such, 
or  mixed  with  the  tar.  A  separate  plant  might 
be  added  to  destructively  distill  to  obtain  rosin 
spirit,  rosin  oil  and  pitch.  The  rosin  itself  might 
be  sold  to  ship  chandlers,  sealing  wax  manufact- 
urers, etc.,  or  when  the  residue  from  the  steam 
process  is  used  for  making  gas,  this  can  be  added 
to  the  wood  to  make  rosin  gas. 

Charcoal. — The  two  chief  methods  of  disposing 
of  this  are  domestic  use  and  for  blast 
furnace  consumption.  In  the  latter  case 
the  advisability  of  encouraging  the  use 
of  brands  or  half-charred  pieces  is  to  be  com- 
mended. In  this  way  destructive  processes  do  not 
take  so  long,  the  tar  is  better  and  the  weight  of 
the  brands  is  greater  than  that  of  the  charcoal. 

The  coke  on  the  bottom  of  the  retort  contains 
considerable  ash.  Probably  the  best  use  of  this 
is  for  fuel,  although  at  many  plants  it  is  thought 
that  this  material  won't  burn.  It  has  been  sug- 
gested to  grind  up  this  material  and  use  it  for 
similar  purposes  as  gas  carbon. 

The  production  of  this  coke  should  be  avoided 
as  far  as  possible  by  careful  operation. 

Residue  from  the  Steam  Process. — The  proper 
disposal  of  this  residue  at  satisfactory  prices  will 
help  solve  the  problem  of  the  utilization  of  waste 
pine  wood.  The  following  are  suggestions:  Side- 
walks in  small  towns  (used  as  such  in  Germany) ; 
fuel,  wall-plaster,  kindling  (by  mixing  with  rosin 
or  yellow  oil) ;  destructive  distillation  in  special 
retorts  for  tar  products  and  gas-making;  oxalic 
acid,  ethyl  alcohol  and  cellulose  products. 

Many  attempts  are  being  made  to  find  a  process 
that  will  enable  the  residue  to  be  converted  into 
paper.  So  far  everything  designed  is  the  reverse 
of  what  it  should  be.  The  paper  industry  is  more 
important  than  the  pine  wood  distillation  industry 
can  ever  hope  to  be.  Instead  of  devising  a  process 
for  making  the  residue  from  a  turpentine  process 


into  paper,  a  process  for  making  paper  which 
will  incidentally  extract  the  turpentine  is  the 
process  that  is  required. 

In  making  paper  the  resin,  which  is  of  impor- 
tance to  the  distiller,  is  a  detriment  to  the  paper- 
maker.  In  making  turpentine  from  pine  wood  only 
fat  wood  is  used,  except  in  a  few  instances.  The 
bulk  of  the  waste  wood  is  not  fat,  consequently 
only  in  those  cases  where  the  waste  is  cheap, 
such  as  sawdust,  can  any  distillation  process  ex- 
tract enough  turpentine  to  pay  for  gathering  the 
wood.  Unless  then,  the  extraction  of  the  turpen- 
tine pays  for  itself,  there  is  nothing  to  be  gained 
in  this  manner,  for  the  paper  manufacturer  can  ob- 
tain his  stock  as  cheaply  without  the  turpentine 
being  extracted. 

To  utilize  waste  wood  by  converting  it  into  pa- 
per, the  proper  place  to  extract  the  turpentine 
would  be  at  the  digester  of  the  paper  mill,  instead 
of  at  the  digester  or  retort  of  a  turpentine  ap- 
paratus. 

The  author  visited  a  paper  mill  using  yellow 
pine  and  found  that  all  that  was  necessary  to  re- 
cover the  turpentine  was  the  placing  of  a  con- 
denser and  a  valved  connecting  pipe  at  the  top  of 
the  digester.  Using  the  soda  process  of  paper- 
making,  the  reaction  in  the  digester  is  carried  out 
at  a  pressure  of  90  to  110  Ibs.,  the  heating  being 
done  by  means  of  steam.  This  action  thoroughly 
extracts  the  turpentine,  more  so  than  many  of 
the  processes  herein  described,  as  the  heat  is  con- 
tiued  longer.  The  action  of  the  caustic  is  not  nec- 
essarily detrimental,  as  it  combines  with  any  tarry 
matters. 

With  a  digester  fitted  with  a  condenser,  all  that 
is  necessary  is  to  open  the  valve  leading  to  the 
condenser,  and  the  oil,  mingled  with  water,  will 
flow  out  from  the  end  of  the  condenser.  The  oil 
is  found  to  be  slightly  yellow,  the  same  as  ordinary 
crude  oil  produced  from  steam  pressure  processes. 
By  a  simple  redistillation  this  can  be  made  white. 

If  all  classes  of  waste  pine  wood  could  be  made 
into  a  quality  of  paper  that  it  would  pay  to  make, 
then  the  above  method  of  extracting  the  turpen- 
tine while  making  paper  solves  the  problem  of 


138 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


the  utilization  of  the  waste  wood  from  pine  and 
fir  wood.  The  question  is  up  to  the  paper  manu- 
facturer, and  not  to  the  wood  distiller. 

An  exception  may  be  made  to  the  above  method 
in  the  case  of  resinous  wood,  but  only  a  small 
quantity  of  the  waste  is  fat.  However,  fat  wood 
could  pass  through  the  above  process  and  be  as 
good  as  it  would  be  if  it  passed  through  any  of 
the  regular  distilling  processes,  except  those  that 
extract  the  resin  by  other  means  than  caustic. 
With  fat  wood  more  caustic  would  be  needed  in 
the  digester  in  order  to  remove  the  excess  of 


resin,  and  this  alkali  could  be  recovered  in  the 
usual  way,  or  with  very  fat  wood,  might  be  neu- 
tralized and  the  resin  recovered.  The  turpentine 
would  come  off  as  usual.  The  quality  of  the  paper 
would  be  the  same,  whether  the  oil  was  recovered 
in  a  regular  distilling  apparatus  or  in  the  diges- 
ter of  the  paper  mill.  It  can  be  readily  under- 
stood that  the  pressure  in  the  digester  can  be  low 
while  the  turpentine  is  being  taken  off,  if  desired. 
Attempts  are  being  made  in  New  York  State  to 
recover  turpentine  from  spruce,  and  the  above 
method,  if  tried,  will  be  found  the  most  suitable. 


CHAPTER  XII. 

CHEMICAL  TESTS  AND  COMBINATIONS. 


In  this  chapter  will  be  recorded  some  of  the  tests 
and  analyses  of  the  different  products  as  made  by 
various  investigators.  Some  have  already  been 
given,  and  they  will  not  be  repeated.  In  addition 
will  be  given  methods  of  combining  the  different 
products. in  order  to  produce  some  of  the  various 
derivatives. 

Turpentine. — The  results  of  the  test  applied  to 
the  turpentine  produced  at  the  Massachusetts  In- 
stitute of  Technology  by  distilling  fat  wood  with 
steam  are  given  "below: 

Specific   gravity    0.865 — 0.867 

Color  some  samples    Water  white 

Spec.    rot.    power +  28.7 

Aci'd   value's    0077    to    .0079% 

Esters  as  bormyl  acetate 7% 

Distilling  below  163  degrees  C 80% 

Distilling  below  175  degrees  C 90% 

Residue   upon    evaporation 0.71   to  1.02% 

(For  others  see  Chapter  X.) 

Tar. — Several  statements  have  already  been 
made  relative  to  the  tests  that  have  been  made  on 
tar.  The  following  are  distillation  tests  on  various 
tars: 

PARTS. 

Ga's 

Light  Heavy  and 

Acid     Oil        Oil     Pitch  loss 
Meiler    tar    from    So.    Austrian 

Black  fir  sp.  gr.   1.075 10         10         15         50          5 

Specific  gravity    (.966)    (1.014) 

Meiler  tar  from  Bohemian  pine 

sp.    gr.    1.116 10          5         15         65          5 

Specific  gravity    (.977)   (1.021) 

Retort    tar    from    Salzburg    sp. 

gr.    1.18    10         10         15         55         10 

Specific  gravity    (1.012)    (1.022) 

Tar  from  distillation  process  by 

superheated  steam   5        20        25        30          5 

Specific  gravity    (.920)     (.978) 

Hardwoods  give  on  an  average  a  tar  which  by 
distillation  yields  according  to  Vincent: 


Watery  distillate  (wood  spirit,  acetic  acid) ...  .10  to  20% 
Oleaginous  light  distillate  sp.  gr.  0.966  to  0.977..  10  to  15% 
Oleaginous  heavy  distillate  sp.  gr.  1.014  to  1.021.10  to  15% 
Pitch  50  to  65% 

ANALYSIS   OF   CHARCOAL. 

Heat  Hydro-  Oxygen 

Product.                        °  C.  Carbo"h,    gen.  &  Loss  Ash 

Dry    wood 150  45.71  6.12  46.29  .08 

Charred    wood    260  67.85  -5.04  26.49  .56 

Red    charcoal    280  72.64  4.70  22.10  .57 

Brown    charcoal    320  73.57  4.83  21.09  .52 

Dull   black    340  75.20  4.41  19.96  .48 

Lustre  black   432  81.64  1.96  15.25  1.16 

Extreme  white  heat.  1500  96.52  0.62  0.94  1.95 

GAS. 
Analyses  of  wood  gas  made  by  Pettenkofer  show: 

Heavy 

Carbonic    Carbonic  Hydro- 

Add          Oxide       Methane  Hydrogen  carbons 
Per  cent..  18  to  25        40  to  50         8  to  12        14  to  17        6  to  7 

Some  gas  purified  gave: 

Heavy 

Carbonic  .  Hydro- 

Oxide         Hydrogen      Marsh  gas    carbons 
Percent 25  to  40  29  to  49  24  to  35  7  to  9 

An  analysis  of  the  gas  from  distilling  fir  made 
at  the  University  of  Washington,  Seattle,  Wash., 
gave  the  following  results: 

Car-                                     Light  Nit- 
Carbon     bon      Hydro-                 hydro-  ro- 
Dioxide  Monoxide  gen    Methane  carbon  gen 
Per     cent 12.3           28.8          80.6           7.3           6.3  14.7 

From  analyses  of  gas  generator  gases: 

Carbonic  acid    10.00  10.70  15.20 

Carbonic  oxide    18.50  17.90  15.40 

Methane     0.70  3.10  7.20 

Hydrogen     17.40  17.60  12.60 

Nitrogen     53.40  50.70  49.60 

The  gas  from  yellow  pine  contains  all  the  above 
ingredients  and  also  some  that  are  characteristic 
of  rosin  gas.  A  gas  made  from  Virginia  pine  by 


140 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


Pettenkofer's  process,  which  consists  in  charring 
the  wood  and  then  pushing  the  charcoal  formed  to 
the  back  of  the  retort  and  letting  the  water  from 
fresh  wood  pass  through  it  while  hot.  analyzed  as 
follows:  Hydrogen,  44  per  cent;  marsh  gas,  5.4 
per  cent;  carbon  monoxide,  33.7  per  cent;  carbon 
dioxide,  10.5  per  cent;  nitrogen,  6  per  cent;  oxygen, 
0.25  per  cent.  A  ton  of  wood  (2,240  Ibs.)  is  said 
to  produce  36,500  cu.  ft.  of  such  gas. 

Ordinary  hardwood  gas  has  tested  26  per  cent 
C  O2  40  per  cent  C  O  and  11  per  cent  marsh  gas, 
the  remainder  being  hydrogen  and  hydrocarbons. 
A  purified  gas  showed  as  follows:  25  per  cent 
marsh  gas,  30  per  cent  hydrogen,  30  per  cent  car- 
bon monoxide,  8  per  cent  hydrocarbons  and  7  per 
cent  carbon  dioxide  and  air.  It  is  difficult  to  puri- 
fy over  lime. 

Tests  of  Pyroligneous  Acid,  Rosin,  Oils,  Etc. — 
The  composition  of  these  compounds  has  been  stat- 
ed under  the  description  of  the  same,  and  it  is  not 
necessary  to  repeat  them  at  this  place.  It  is  well 
to  again  call  attention  to  the  fact  that  those  woods 
which  are  hard  containing  relatively  large  amounts 
of  lignin  and  incrusting  substances  give  larger 
yields  of  acetic  acid  and  methyl  alcohol  than  those 
woods  containing  but  small  amounts  of  this  harder 
material  and  consequently  called  soft  wood. 

Combinations   or    Derivatives. 

Turpentine  Derivatives. 

Camphor  do  H™  O. 

The  most  important  derivative  of  turpentine  is 
camphor.  To  prepare  two  general  methods  are 
pursued:  one  is  to  treat  the  turpentine  direct  with 
suitable  reagents,  and  the  other  is  to  first  change 
the  pinene  into  pinene  hydrochloride  from  which 
camphor  can  be  made. 

The  first  method  was  tried  unsuccessfully  in  this 
country,  but  it  is  of  interest  nevertheless.  The 
process  used  was  that  of  Thurlow,  which  consists 
in  heating  the  turpentine  with  anhydrous  oxalic 
acid  at  a  temperature  below  120  degrees  C. 

According  to  Collins,  the  process  is  carried  out 
on  a  small  scale,  as  follows  :  In  a  steam-jacketed 
reaction  tank,  oil  of  turpentine  and  anhydrous 


oxalic  acid  are  placed,  the  results  of  the  reaction 
being  pinyl  oxalate  and  pinyl  formate.  The  liquid 
mass  formed  is  pumped  into  a  set  of  stills  for  treat- 
ment. Here  it  is  distilled  with  live  steam  in  the 
presence  of  an  alkali,  the  resultant  formation  oc- 
curring as  ordinary  camphor  and  borneol  camphor 
dissolved  in  the  oily  products  of  the  reaction. 
These  oils  are  fractionally  distilled  to  extract  the 
camphor  and  borneol  further.  After  the  pleasant 
smelling  oils  have  passed  over,  the  camphor  and 
borneol  distill  in  the  steam  and  are  precipitated  in 
the  condenser  in  a  white  mass  somewhat  resem- 
bling boiled  rice.  The  crude  product  is  then  forced 
by  compressed  air  through  a  filter  press  and  thor- 
oughly washed  to  free  it  from  all  traces  of  oil, 
when  it  is  dropped  into  an  oxidizing  tank,  where 
the  borneol  oxidizes  into  the  ordinary  camphor. 

The  mass  is  transferred  to  a  rapidly  revolving 
centrifugal  machine,  where  the  oxidizing  liquors 
are  thrown  out  and  the  camphor,  being  heavier,  re- 
mains behind  comparatively  pure,  but  stained  from 
the  oxidizing  compound,  so  that  it  resembles  light 
brown  sugar.  After  removal  from  the  separator 
it  is  placed  in  a  large  steam  jacketed  sublimer.  In 
this  vessel  a  slow  heat  frees  it  from  any  water 
it  may  contain,  and  the  temperature  is  then  raised 
to  the  boiling  point  of  camphor  and  a  rapid  current 
of  air  projected  over  the  surface  of  the  pan,  blow- 
ing the  camphor  into  a  condensing  chamber,  where 
it  settles  in  the  form  of  snowflake-like  crystals. 

The  yield  of  camphor  by  this  process  is  from  25 
to  30  per  cent  of  the  weight  of  the  turpentine  used. 
In  addition  to  camphor,  there  are  a  number  of  light 
oils  produced  in  the  process,  which  are  also  found 
in  nature,  namely,  dipentene,  oil  of  lemon,  oil  of 
lime  and  a  number  of  other  natural  terpenes  and 
essential  oils.  This  process  of  synthetically  pro- 
ducing camphor  takes  about  fifteen  hours. 

In  most  of  the  other  processes  pinene  hydrochlo- 
ride is  formed  by  passing  dry  hydrochloric  acid  gas 
into  dry  turpentine  oil,  both  being  well  cooled.  If 
a  rise  in  temperature  is  prevented  during  the  reac- 
tion the  oil  solidifies  almost  completely  after  sat- 
uration with  the  gas  to  a  camphorlike  mass.  Some 
pass  the  gas  into  a  mixture  of  turpentine  and  chlo- 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


141 


reform  and  distill  off  the  chloroform  and  then  the 
hydrochloride. 

This  product  is  called  artificial  camphor  Cio  Hie. 
H  Cl.  It  melts  at  125  degrees  C.  and  boils  at  208 
degrees,  suffering  almost  no  decomposition. 

The  conversion  of  this  product  into  camphor  is 
based  on  the  fact  that  when  the  hydrochloric  acid 
Is  removed  by  a  feeble  alkali,  such  as  aniline,  or 
by  means  of  sodium  acetate  and  acetic  acid,  the 
compound  formed  is  not  pinene,  as  would  be  ex- 
pected, but  camphene,  a  terpene  closely  allied  to 
camphor,  which,  by  oxidation,  can  be  converted  into 
camphor. 

A  process  patented  in  this  country  uses  lime  to 
remove  the  chlorine  and  then  oxidizes  the  cam- 
phene with  nitric  acid.  It  is  doubtful  if  much  cam- 
phor would  be  produced  when  lime  is  used. 

A  general  method  for  the  production  of  cam- 
phene is  to  heat  pinene  hydrobromide  or  hydro- 
chloride  with  sodium  acetate  and  glacial  acetic 
acid  at  200  degrees  C. 

The  oxidation  of  the  camphene  to  camphor  may 
be  performed  in  the  following  manner,  using  isobor- 
neol  as  an  intermediary: 

Two  hundred  and  fifty  parts  by  weight  of  glacial 
acetic  acid  and  ten  parts  by  weight  of  50  per  cent 
sulphuric  acid  are  mixed  with  100  parts  by  weight 
of  camphene  and  the  whole  heated  to  50  degrees 
to  60  degrees  C.  for  a  few  hours  and  the  mixture 
frequently  agitated.  Two  layers  are  formed  at  first, 
but  after  a  short  time  a  perfectly  clear  slightly  col- 
ored or  colorless  solution  results.  The  reaction  is 
complete  in  two  or  three  hours  and  the  product  is 
diluted  with  water,  the  resultant  isoborneol  acetate 
separating  as  an  oil.  This  is  washed  a  few  times 
to  remove  the  free  acid,  and  without  further  puri- 
fication it  is  boiled  for  a  short  time  with  a  solu- 
tion of  50  parts  by  weight  of  potassium  hydroxide 
in  250  parts  by  weight  of  ethyl  alcohol  in  a  still 
connected  with  a  reversed  condenser.  The  greater 
part  of  the  alcohol  is  then  distilled  off  and  the 
residue  poured  into  a  large  quantity  of  water;  iso- 
borneol is  precipitated  as  a  solid  mass,  which  can 
be  separated  pure  by  filtering  and  recrystallizing 
from  petroleum  ether.  The  isoborneol  is  then  oxi- 


dized with  just  enough  nitric  acid,  or  with  a  solu- 
tion of  chromic  anhydride  in  glacial  acetic  acid, 
the  resulting  product  being  camphor. 

Instead  of  using  isoborneol  itself,  a  German  pro- 
cess starts  with  isoborneol  acetate  or  benzoate. 
The  oxidation  may  be  performed,  for  instance,  by 
means  of  chromic  acid,  nitric  add,  permanganate, 
manganese  and  sulphuric  acid,  Caro's  acid,  etc., 
working  either  in  solution  or  in  suspension.  The 
following  formulas  are  given: 

Ex.  1.— One  hundred  and  twenty-seven  parts  by 
weight  of  isoborneol  acetate  are  dissolved  in  2,000 
parts  by  weight  of  glacial  acetic  acid  or  other  suit- 
able acid,  which  is  not  affected  by  the  oxidizing 
agent,  and  then  oxidized  with  78  parts  by  weight 
of  chromic  acid.  The  reaction  being  completed, 
the  excess  of  solvent  is  distilled  off,  the  residue 
washed  out  with  water  and  purified  in  the  usual 
manner. 

Ex.  2. — One  hundred  and  twentyseven  parts  by 
weight  of  isobornyl  acetate  are  well  mixed  with 
78  parts  by  weight  of  chromic  acid  in  2,000  parts 
by  weight  of  water,  at  about  90  degrees  C.,  until 
no  more  free  chromic  acid  is  present.  After  cool- 
ing the  raw  camphor  crystallizes  out  and  is  then 
purified  in  the  usual  way. 

Ex.  3.— One  hundred  and  seventy  parts  by  weight 
of  isobornyl  benzoate  are  well  mixed  with  78  parts 
by  weight  of  chromic  acid  in.  2,000  parts  by  weight 
of  water  at  a  temperature  of  about  90  degrees 
centigrade  for  so  long  as  no  more  free  chromic  acid 
can  be  identified.  After  cooling,  the  former  raw 
camphor  is  separated  from  the  adhering  benzoic 
acid  by  boiling  with  alkalies,  and  is  further  purified 
in  the  usual  way. 

There  are  a  great  many  patented  processes  us- 
ing the  hydrochloride  as  a  basis.  One  decomposes 
the  hydrochloride  with  phenols,  etc.,  and  oxidizes 
the  camphene  in  the  usual  manner. 

Another  dries  the  turpentine  with  calcium  carbid 
and  then  treats  slowly  with  dry  H  Cl  gas  at  30  de- 
grees C.  The  compound  thus  formed  is  heated  to 
180  degrees  C.  with  a  metal  and  oxidizing  agent, 
such  as  zinc  and  barium  peroxide  and  sodium  anJ 


142 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


peroxide.     It  is  stated  that  when  manganese  diox- 
ide is  used  alone  no  metal  is  necessary. 

Also  from  camphene  when  treated  with  chromic 
acid  mixture  at  180  degrees,  ozonide  (do  Hie  Os) 
is  formed,  and  this  treated  with  water  loses  oxygen 
to  form  a  lactone,  camphenolide,  and  by  heating 
this  compound  in  presence  of  water,  camphor  is 
formed. 

Terpine  Hydrate  do  His  (OH)2  +  H2  O—  The 
following  is  Hempel's  method  of  production:  A 
mixture  of  eight  parts  of  turpentine  oil,  two  parts 
of  alcohol  and  two  parts  of  nitric  acid  of  sp.  gr. 
1.255  is  well  mixed  and  placed  in  flat  basins.  After 
standing  for  a  few  days  the  mother  liquor  is  poured 
off  from  the  crystals  of  terpine  hydrate,  and  neu- 
tralized with  an  alkali,  after  which  a  second  crop 
of  crystals  separate.  Terpine  hydrate  can  be  found 
in  any  pharmacy. 

Cineole  do  His  O.— This  is  found  in  the  oil  of 
eucalyptus  and  other  oils.  In  making  the  above 
compound  (terpine  hydrate)  the  mother  liquor  is 
found  to  contain  this  product.  Its  formation  is 
probably  due  to  the  action  of  the  dilute  acid,  on 
terpine  hydrate  and  terpineol.  By  distilling  the 
mother  liquor  from  the  manufacture  of  terpine  hy- 
drate with  steam  and  cooling  to  a  low  tempera- 
ture the  oil  found  in  the  distillate,  the  cineole  will 
separate,  or  by  treating  the  distilled  oil  with  con- 
centrated phosphoric  acid  and  neutralizing  the  re- 
sulting compound  with  an  alkali  cineole  will  be 
produced.  Cineole  is  a  liquid  with  an  odor  resemb- 
ling camphor.  It  has  a  specific  gravity  0.930  at  15 
degrees  C.  and  a  refractive  index,  N  D  =  1.45961  at 
17  degrees. 

Terpineol  do  HIT  O  H. — It  has  been  mentioned 
that  the  yellow  oil  left  after  distilling  the  turpen- 
tine from  the  crude  oil  from  the  steam  distillation 
of  pine  wood  may  be  a  terpineol.  There  are  three 
of  these  compounds  recognized  and  one  form  is 
solid.  Terpineol  is  produced  from  terpine  hydrate 
by  the  action  of  dilute  acids.  It  may  also  be  pro- 
duced by  the  action  of  formic  acid  on  geraniol  at 
a  temperature  of  15  degrees  to  20  degrees.  The 


terpinyl  formate  formed  is  changed  to  terpineol  by 
hydrolysis.     Terpineol  is  found  in  many  oils. 

A  more  extended  description  of  these  derivatives 
cannot  be  given  here.  They  are  given  to  illustrate 
the  possibilities  of  utilizing  the  turpentine  if  the 
market  prejudice  continues  to  exist. 

Rosin  Derivatives. — It  has  been  stated  that  the 
rosin  can  be  employed  in  many  ways,  one  of  which 
is  by  distilling  it  for  other  products.  The  action 
of  heat  on  rosin  should  be  known  by  a  pine  wood 
distiller,  so  the  following  methods  are  given: 

A  still  or  retort  may  be  a  vertically  placed 
wrought  iron  cylinder,  or  the  cylinder  may  be 
placed  horizontally.  Some  use  a  regular  still  shaped 
like  a  coal  tar  still.  Whatever  shape  is  used  is 
connected  with  a  suitable  copper  condenser  and 
heated  by  means  of  a  direct  fire.  The  size  of  the 
still  varies,  but  usually  is  large  enough  to  contain 
fifty  to  seventy  barrels  of  rosin. 

The  flow  commences  in  about  one  to  one  and  a 
half  hours  after  firing,  and  continues  until  there 
only  remains  in  the  still  a  charry  mass  resembling 
coal.  The  distillation  period  covers  a  space  of  about 
twenty-four  hours. 

The  best  oil  is  obtained  between  the  fifth  and 
twenty-second  hours  running,  and  is  of  a  pale  yel- 
lowish brown  color.  It  then  begins  to  darken,  and 
after  an  hour  or  an  hour  and  a  half  the  result  is  a 

very  black  gumming  oil.     The   firing  is   generally 

v 
stopped  before  this  time  on  account  of  the  difficulty 

in  removing  the  residuum  from  the  bottom  of  the 
still. 

According  to  Renard,  that  portion  of  the  distil- 
late boiling  under  360  degrees  C.  is  called  rosin 
spirit  and  that  which  boils  above  360  degrees  C.  is 
called  rosin  oil.  This  point  is  also  marked  by  the 
falling  off  in  the  quantity  of  the  distillate  and  by 
the  specific  gravity  of  the  distillate  showing  about 
.951.  The  residuum  when  not  completely  charred  is 
called  pitch  and  the  last  product  coke.  The  gas 
produced  is  very  heavy  and  a  powerful  anaesthetic, 
containing  carbonic  oxides,  ethylene,  butylene  and 
pentine. 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


143 


The  products  from  a  seventy-barrel  still  are  given 
below: 

Name  of  product.  Amounts         Yield  % 

Rosin    spirit    60-70  gals.  3.1 

Rosin   oil    1600  gal's.  85.1 

Coke    600-700  gals.  3.9 

Acid  and  water   40-50  gals.  2.5 

Gas  and  loss   5.4 

The  yield  from  an  actual  run  made  at  a  plant 
in  Pennsylvania  were  as  follows: 

Amount  of  rosin 5650  Ibs.  Per  ct. 

Naphtha    or    spirit about    100  Ibs.  approx.       1.75 

Raw  oil   or  rosin   oil about  4960  Ibs.  approx.     87.50 

Water     about       47  Ibs.  approx.       0.80 

Pitch     about     210  Ibs.  approx.       3.76 

Gase's,   loss,   etc about     350  Ibs.  approx.       6.20 

Apparently,  this  run  shows  more  oil  and  less 
spirit  than  the  seventy-barrel  charge,  but  the  raw 
oil  upon  boiling  gave  off  a^out  6.2  per  cent  of  wa- 
ter and  naphtha. 

In  Russian  plants  about  ll/2  Per  cent  of  lime  is 
added  to  the  rosin  in  the  still. 

The  pi-ne  oil  or  rosin  spirit  is  refined  in  a  man- 
ner very  similar  to  turpentine,  by  simple  washing 
with  water  and  redistilling  once  or  twice.  Some- 
times caustic  soda,  or  other  alkali  is  added  before 
distilling,  in  order  to  remove  rosin  oils  and  acid. 
Most  of  the  rosin  oil  on  the  market  is  obtained  by 
one  distillation.  It  is  improved  by  redistilling  in 
the  same  manner  as  it  was  obtained.  Sometimes 
the  oil  is  distilled  three  times  after  coming  from 
the  first  still,  each  grade  being  known  as  first  (from 
the  rosin),  second,  third  and  fourth  run. 

Formerly  gas  of  high  quality  was  made  from  the 
rosin,  100  Ibs.  furnishing  1,300  cu.  ft.  Rosin  spirit 
is  used  as  a  substitute  for  the  oil  of  turpentine 
and  is  known  as  pinolene  and  pine  oil. 

Rosin  oil  is  about  one-fourth  soluble  in  soda  so- 
lution, the  other  three-quarters  being  comprised 
largely  of  hydrocarbons  (above  360  degrees  C.). 

To  make  rosin  grease,  a  smooth  cream  of  slacked 
lime  and  water  is  first  prepared  and  a  small  por- 
tion of  the  oil  is  mixed  with  this  in  the  proportion 
of  about  four  parts  of  oil  to  three  parts  of  slacked 
lime.  Oil  is  then  added  to  the  greasy  semi-solid 


mass  until  of  the  required  consistency.  The  fin- 
ished grease  is  often  composed  of  about  1  part  of 
lime  to  20  to  25  of  oil.  Various  terms  are  applieJ 
to  crude  oil,  such  as  blue,  green,  red,  kidney  and 
heavy,  according  to  the  characteristics  thereof. 

The  pitch  formed  by  the  destructive  distillation 
of  rosin,  as  well  as  that  made  by  boiling  down  tar. 
is  the  ordinary  pitch  of  commerce.  Rosin  pitch  i& 
different  from  tar  pitch  in  color,  properties  and 
composition,  yet  it  is  near  enough  like  it  for  most 
practical  purposes.  It  is  yellowish  brown,  brittle, 
compact,  easily  crumbling  between  the  fingers.  Its 
specific  gravity  is  1.09  and  it  melts  at  68  degrees 
C.  It  loses  82%  per  cent  on  heating,  leaving  a 
spongy,  soft  coke.  It  has  an  odor  of  rosin  when 
heated.  It  is  soluble  in  benzine  and  pyridin. 

Wood  Residues. 

Oxalic  Acid. — The  action  of  strong  alkalies  upon 
wood  is  to  convert  the  cellulose  into  oxalic  acid, 
which  combines  with  the  alkali  to  form  an  oxalate. 
There  are  several  methods  of  making  oxalic  acid 
by  this  general  process,  varying  in  the  proportion 
and  kind  of  alkali  used  and  the  method  of  convert- 
ing the  resulting  oxalate  into  oxalic  acid.  A  mix- 
ture of  caustic  potash  and  caustic  soda,  40  parts 
K  O  H  and  60  parts  of  Na  O  H,  seems  to  be  the 
cheapest  proportion  of  alkali.  Soft  woods  give  the 
larger  yield,  thin  layers  are  better  than  thick  lay- 
ers. It  would  seem  to  be  better  to  use  those  pro- 
portions of  wood  and  alkali  as  would  give  the  larg- 
est percentage  of  oxalic  acid  as  compared  with  the 
amount  of  alkali  used,  but  difficulties  in  the  work- 
ing of  the  process  allow  of  not  more  than  50  parts 
of  sawdust  to  100  of  alkali.  The  oxalic  acid  is 
formed  chiefly  from  the  cellulose  of  the  wood  and 
not  from  the  lignin. 

A  detailed  description  of  the  making  of  oxalic 
acid  can  be  found  elsewhere.  A  general  descrip- 
tion of  one  process  only  will  be  given  here. 

Fine  sawdust  is  gradually  added  to  a  strong  so- 
lution of  iy2  parts  caustic  potash  and  one  part  caus- 
tic soda,  contained  in  iron  pans.  The  mixture  is 
then  evaporated  with  constant  stirring  so  as  to 
obtain  a  moist,  powdery  residue.  At  first  only 


144 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


water  is  removed  but  gradually  the  mass  turns 
darker  and  the  wood  begins  to  decompose  and  emit 
a  pungent  odor.  At  a  temperature  of  about  180 
C.  the  mass  becomes  a  greenish  yellow.  The  tem- 
perature should  be  gradually  raised  .to  about  240 
C.  and  held  there  until  the  wood  is  dissolved,  the 
total  time  being  about  six  hours.  The  resulting 
material  consists  of  a  mixture  of  sodium  and  potas- 
sium oxalates  and  carbonates  with  some  impurities 
from  the  decomposition  of  the  wood,  which  gives  it 
a  distinct  color. 

To  extract  the  oxalate  the  material  is  thrown 
into  iron  filter  boxes  with  wire  gauge  false  bot- 
toms, and  the  potassium  washed  out  with  water 
drawn  through  the  mass  by  means  of  a  vacuum 
pump.  The  residue  consists  of  sodium  oxalate, 


from  wood  has  long  been  attempted.  When  cellu- 
lose is  treated  with  dilute  acid  it  is  converted  into 
a  fermentable  sugar.  Soft  woods  are  the  best,  as 
they  contain  relatively  more  cellulose.  So  far,  a 
great  many  difficulties  have  been  encountered  in 
the  practical  manufacture  of  spirits  which  have  not 
been  entirely  overcome.  The  acid  used  may  be 
suitable  for  the  production  of  the  bugar,  but  when 
the  acid  is  neutralized  with  lime  the  resulting  prod- 
uct interferes  with  the  fermenting;  when  sulphuric 
acid  is  used  it  seems  to  prevent,  in  a  measure,  the 
conversion  of  the  cellulose  into  alcohol,  although 
the  calcium  sulphate  formed  does  not  interfere 
with  the  fermentation.  .  The  following  conditions 
seem  to  be  necessary  to  obtain  the  best  results 
with  ordinary  mineral  acids  and  soft  woods: 


Wood  Cellulose   (bisulphite) 

Proportion    of    total    liquiu 6  times  \\  t.  of  cellulose 

Concentration  of  acid    0.5   per   cent   H2   SO* 

Pressure    10  atmospheres 

Duration   of  digestion    1%  hours 

Yield  sugar   (Fehling's  test) 41  per  cent 

Fermentation    Free 

Yield  of  alcohol  from  sugar 70%  of  theoretical 


Pine  Wood. 
5  times  wt.  of  wood 
0.5%  H2  SO4 
9  atmospheres 
15   minutes 
20%  of  wood 
Variable 
60%  highest 


which  is  decomposed  by  heating  with  milk  of  lime 
in  an  iron  pan  supplied  with  a  horizontal  stirrer,. 
calcium  oxalate  and  caustic  soda  being  formed.  By 
evaporating  the  soda  lye  it  can  be  used  again.  The 
calcium  oxalate  after  it  has  been  washed  with  wa- 
ter is  decomposed  by  sulphuric  acid  in  wooden  vats 
lined  with  lead. 

The  potash  salts  washed  out  from  the  crude 
oxalate  in  the  first  operation  are  also  boiled  with 
lime  to  recover  the  caustic  potash,  which  is  also 
used  again.  The  oxalic  acid  formed  by  decompos- 
ing the  calcium  oxalate  with  sulphuric  acid  is 
evaporated  and  crystallized  repeatedly  in  lead  pans 
until  sufficiently  free  from  sulphuric  acid.  The 
mother  liquor  mixed  with  more  sulphuric  acid  is 
used  to  decompose  more  calcium  oxalate. 

Ethyl  Alcohol. — The  preparation  of  grain  alcohol 


Under  properly  controlled  conditions,  one  long 
ton  of  wood  should  yield  a  little  over  17  gallons 
of  absolute  alcohol. 

The  variation  in  the  fermentation  of  sugars  is 
due  to  the  presence  of  pentoses,  which  are  not  fer- 
mentable, the  hexoses  only  being  decomposed  by 
the  yeast. 

One  experimenter  using  European  pine  sawdust 
made  only  seven  gallons  of  absolute  alcohol  from 
a  short  ton. 

Another,  working  on  a  large  scale,  succeeded  in 
obtaining  about  19  gallons  of  absolute  alcohol  from 
a  long  ton  of  sawdust  containing  20  per  cent 
moisture,  equal  to  nearly  24  gallons  to  the  ton  of 
dry  sawdust.  The  quality  of  the  sawdust  is  said 
to  be  most  satisfactory,  there  being  no  turpentine 
flavor  or  odor. 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


145 


A  process  for  making  alcohol  on  this  principle 
proposes  to  use  sulphurous  acid  instead  of  sul- 
phuric acid,  or  other  mineral  acid  previously  used. 
This  process  is  known  as  Classen's  process.  Sul- 
phurous acid  (formed  by  passing  sulphuric  dioxide 
into  water)  easily  loses  this  sulphur  dioxide  when 
heated,  consequently  when  wood  is  treated  with 
this  acid  and  sugar  formed  the  acid  can  be  decom- 
posed by  heat  and  the  sugar  solution  left  ready 
for  fermentation  and  containing  nothing  to  seri- 
ously interfere  with  the  fermentation  process.  The 
sulphur  dioxide  formed  by  the  decomposition  of 
the  sulphurous  acid  can  be  recovered  by  passing 
it  through  water. 

A  company  with  a  large  capital  is  attempting  to 
utilize  pine  wood  sawdust  in  this  manner  at  Hat- 
tiesburg,  Miss.  The  author  has  not  attempted  to 
obtain  the  details  of  the  process  as  carried  out  by 
this  company,  and  has  no  information  as  to  the 
success  of  the  venture. 

The  general  principles  of  the  Classen  process  are 
known,  and  can  be  briefly  stated. 

The  steps  in  the  process  are  as  follows: 

1.  The   manufacture  of   the     sulphurous     acid, 
which'  is  done  by  simply  passing  sulphur  dioxide 
gas  into  water.     This  gas  can  be  made  by  burning 
sulphur  in  suitable  receptacles  or  from  pyrites. 

2.  The  treatment  of  the  wood  with  the  weak  sul- 
phurous acid,  under  pressure  in  a  steam  jacketed 
rotary  digester.    • 

3.  The  blowing  off  of  the  gas  and  steam  from 
the  digester  to   recover  the  acid. 

4.  The    removal    of    the    treated    sawdust    into 
leaching  or  exhausting  vats,   where  the   sugar  is 
washed  out  with  water. 

5.  The   neutralizing  of  the   sugar  solution  thus 
produced  by  means  of  carbonate  of  lime  or  other 
alkali. 

6.  The  fermenting  of  the  sugar  solution. 

7.  The    distilling    of   the    alcohol    as    ordinarily 
carried  out  in  distilleries. 

The  conditions  of  working  should  be  carried  out 
very  closely.  An  acid  solution  of  about  one-third 
the  weight  of  sawdust  is  used  in  the  digester.  The 
digester  is  slowly  turned  and  the  steam  in  the  out- 


side jacket  heats  the  contents  of  the  digester  to 
approximately  295  degrees  Fah.  The  pressure  rises 
to  100  Ibs.,  or  more,  to  the  square  inch,  and  is 
maintained  for  about  three  hours.  By  the  action 
of  the  acid  some  of  the  cellulose  is  changed  to 
sugar.  By  blowing  out  the  steam  and  acid  into  ab- 
sorbing tanks  75  to  80  per  cent  of  the  acid  is  re- 
covered. 

To  extract  the  sugar  from  the  treated  sawdust, 
the  material  is  removed  from  the  digester  and 
put  into  a  series  of  tanks  similar  to  a  diffusion 
battery.  Here  fresh  water  enters  the  tank  con- 
taining residue  with  a  small  amount  of  sugar,  and 
then  passes  to  another  containing  residue  with 
a  larger  proportion  of  sugar,  and  so  on  until  the 
tank  containing  the  material  fresh  from  the  diges- 
ter is  reached,  from  whence  it  passes  to  the  neu- 
tralizing vats.  In  this  manner  the  sugar  is  ex- 
tracted from  the  treated  sawdust  with  the  use  of 
but  little  water,  and  makes  a  much  stronger  sugar 
solution  than  if  each  tank  was  washed  separately. 
Generally,  the  contents  of  each  tank  is  washed  ten 
times  before  removing  the  residue. 

A  yield  of  450  to  500  Ibs.  of  sugar,  about  70  to  90 
per  cent  of  which  is  fermentable,  is  claimed  as  the 
yield  from  a  long  ton  of  dry  sawdust.  This  sugar 
is  in  a  dilute  acid  solution,  which  must  be  nearly 
neutralized  so  that  the  acid  will  not  affect  the 
action  of  the  yeast  which  is  added  to  the  solution, 
to  cause  alcoholic  fermentation.  This  neutralizing 
and  fermenting  is  done  in  suitable  tanks  and  vats. 
The  fermenting  must  be  done  at  the  proper  tem- 
perature and  when  finished  the  "mash"  is  distilled 
in  column  stills.  The  yield  is  claimed  to  be  25 
gallons  of  absolute  alcohol  per  long  ton  of  dry 
sawdust. 

The  residue,  consisting  chiefly  of  lignin  and  oth- 
er matter  not  acted  upon  by  the  acid,  and  amount- 
ing from  two-thirds  to  three-quarters  of  the  volume 
of  the  original  wood,  can  be  used  for  fuel,  or  other- 
wise treated.  When  sawdust  is  acted  upon  by 
acids  it  loses  its  elasticity  and  consequently  can 
be  easily  moulded  into  briquettes,  which  can  be 
used  for  fuel  or  destructively  distilled. 
Whether  the  process  will  be  successful  or  not 


146 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


remains  to  be  seen.     It  requires  careful  attention 
to  details  to  obtain  the  best  results. 

Tar  and  Derivatives. — The  chief  derivatives  from 
tar  would  be  the  products  of  distillation.  The 
products  of  the  destructive  distillation  of  tar  have 
been  mentioned,  and  in  the  first  part  of  this  chap- 
ter a  table  is  given  showing  the  amount  of  the 
various  products  obtained  by  distillation  of  various 
kinds  of  tar. 

The  distilling  operation  is  smilar  in  all  cases, 
the  yield  of  the  different  products  varying  accord- 
ing to  the  quality  of  the  tar.  In  distilling  pine 
tar  from  retorts  the  light  oils  should  first  be  re- 
moved by  steam  and  the  tar  remaining  treated  be- 
fore distillation  by  washing  with  lime  water  to  re- 
move acid.  Of  course,  this  acid  can  be  distilled 
off  if  desired,  thus  making  the  use  of  lime  unnec- 
essary. 

Starting  with  neutral  and  water  free  tar,  the  tar 
is  placed  in  a  still  made  of  wrought  or  cast  iron, 
the  latter  being  preferred  for  small  stills,  as  the 
tar  can  be  easily  coked  in  them  if  required.  These 
stills  are  generally  made  a  little  over  two-thirds 
as  high  as  the  diameter  and  furnished  with  suit- 
able inlet  valves  at  the  side  near  the  top  and  an 
outlet  pipe  at  the  bottom  for  withdrawing  the  hot 
pitch.  To  keep  the  tar  from  boiling  over,  and  to 
help  heat  the  mass  more  evenly,  a  stirrer  is  pro- 
vided. Sometimes  the  bottom  is  made  concave,  so 
that  the  fire  can  come  nearer  the  middle  of  the 
still.  On  the  top  of  the  still  is  a  spherical  head, 
from  which  comes  a  pipe  leading  to  the  condenser. 
Usually  the  still  is  entirely  bricked  in  to  prevent 
radiation. 

The  still  is  heated  very  slowly  for  the  first  five 
or  six  hours.  The  best  tar  contains  some  water, 
and  this  causes  a  noise  in  the  still.  This  water 
distills  first  and  is  followed  by  light  oil,  or  oil  of 
tar,  as  it  is  called  at  the  pharmacies.  This  oil 
quickly  turns  brown  on  exposure  to  the  air.  The 
receiver  is  changed  when  the  sp.  gr.  of  the  oil 
reaches  about  0.98.  Following  the  light  oils  a 
heavy  oil  comes  over,  having  a  sp.  gr.  of  upwards 
of  1.01  and  a  yellowish  green  color.  The  distilla- 
tions can  be  continued  until  nothing  but  coke  re- 


mains in  the  still,  but  this  is  so  difficult  to  remove 
that  it  is  best  to  stop  with  the  production  of  pitch, 
which  can  be  drawn  out  hot  from  the  still,  if  prop- 
er care  is  taken  to  prevent  it  from  igniting.  This 
pitch  can  be  run  out  on  iron  plates  and  broken  up 
for  fuel,  or  used  for  similar  purposes  as  coal  tar 
pitch. 

Some  make  the  distillation  according  to  tem- 
perature, the  oil  collected  under  150  degrees  C.  be- 
ing called  light  oil,  and  that  collected  above  150 
degrees  C.  is  known  as  heavy  oil.  Some  collect 
the  light  oils  up  to  240  degrees  C.  and  the  heavy 
oils  between  240  degrees  C.  and  290  degrees  C., 
this  latter  method  not  being  common. 

The  oils  are  often  washed  with  caustic  soda  and 
redistilled,  the  light  oils  being  used  as  a  substitute 
for  turpentine.  The  heavy  oil  contains  most  of  the 
creosote,  amounting  to  about  15-25  per  cent  in  pine 
tar  oil  and  about  17  per  cent  in  the  creosote  oil 
of  the  fir,  being  in  the  latter  case  5  per  cent  of 
the  tar.  The  usual  method  of  obtaining  creosote 
is  to  treat  the  heavy  oil  with  strong  lye  of  about 
1.20  sp.  gr.  Usually  a  small  sample  is  treated 
first,  in  order  to  determine  about  how  much  soda 
is  needed.  This  alkaline  solution  is  drawn  off  from 
the  remaining  oil.  Often  both  oils  are  mixed  after 
neutralizing  with  the  soda,  and  then  rectified  by 
distillation.  The  receiver  is  changed  as  soon  as 
the  temperature  rises  above  302  degrees  F.,  and  is 
changed  again  when  the  temperature  rises  above 
482  degrees  F.  Some  take  the  fraction,  between 
150  degrees  and  250  degrees. 

The  rectification  and  treatment  with  soda  is  re- 
peated many  times  in  some  cases,  but  finally  the 
light  oil  is  collected  separately  from  /he  heavier. 
The  light  oils  thus  produced  contain  mostly  xylol, 
but  also  eupion  and  kapnomar;  the  heavy  oil  con- 
tains the  paraffin. 

The  alkaline  liquors  have  absorbed  the  creosote. 
These  liquors  are  then  boiled  in  an  open  pan  to 
expel  hydrocarbons,  and  when  cooled  saturated 
with  sulphuric  acid  and  allowed  to  repose.  The 
fluid  separated  thereby  is  creosote.  This  is  some- 
times again  dissolved  in  alkali  and  reprecipitated 
with  sulphuric  acid  until  entirely  soluble  in  caus- 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


147 


tic  soda.  In  either  case  it  should  afterwards  be 
distilled  and  the  middle  portions,  collected  between 
200  degrees  and  and  220  degrees  C.,  are  called 
commercial  wood  creosote.  To  further  purify  it, 
it  is  treated  with  %  to  l/2  per  cent  of  potassium 
bichromate  and  y2  to  1  per  cent  of  sulphuric  acid, 
allowed  to  repose  twenty-four  hours  and  again  dis- 
tilled. The  distillation  is  generally  carried  on  in 
glass  vessels,  the  portions  between  205  degrees 
and  220  degrees  C.  being  collected  separately. 

Wood  creosote  is  a  colorless,  highly  refracting 
oil  with  a  sp.  gr.  of  1.03  to  1.087,  and  a  boiling 
point  from  205  degrees  to  222  degrees  C.  Stock- 
holm creosote  from  pine  tar  consists  chiefly  of 

fOCHs 
creosol    C«   Hs    (C  Hs)  \  OH       Wood    tar    creosote 

does  not  solidify  with  moderate  cold;  it  is  a  pow- 
erful disinfectant,  but  does  not  disintegrate  like 
phenol  is  apt  to  do.  It  is  insoluble  in  water,  but 


readily  so  in  ether,  alcohol,  glacial  acetic  acid, 
chloroform,  benzine  and  carbon  bisulphide.  Fif- 
teen parts  of  wood  creosote  with  ten  of  collodion 
dissolve  to  a  clear  solution,  whereas  under  the 
same  conditions  coal  tar  creosote  forms  a  gelatin- 
ous mass.  Crude  wood  creosote  contains,  in  addi- 
tion to  creosol,  jphloral,  guaiacol,  etc.,  eupion, 
kapnomar,  picamar,  cedriret,  pyrene,  pittacal,  etc. 
and  these  can  be  recovered  from  wood  tar.  Such 
are  not  commercially  important. 

The  pitch  formed  in  the  still  by  distilling  the 
tar  comprises  a  large  bulk  of  the  original  tar. 
There  is  still  left  about  88  per  cent  of  volatile 
matter,  which  can  be  removed  by  heating,  leaving 
12  per  cent  of  soft  friable  coke. 

This  pitch  is  soluble  to  a  large  extent  in  alco- 
hol, potash,  benzine,  etc.  It  contains  some  vola- 
tile fatty  acids  and  hydrocarbons.  See  Pitch, 
Chapter  X. 


CHAPTER  XIII. 

CHEMICAL  CONTROL  OF  A  PLANT  FOR  THE  DISTILLATION  OF  WOOD. 


The  destructive  distillation  of  wood  is  as  much 
a  chemical  operation  as  the  distillation  of  petro- 
leum. Very  few  manufacturing  industries  using 
destructive  distillation  processes  employ  chemists. 
One  of  the  best  known  of  these  industries  is  'the 
coal  gas  manufacture  and  it  is  only  recently  that 
chemists  have  been  used  at  these  plants  even 
in  large  cities.  One  reason  is  that  the  field  has 
been  occupied  more  by  engineers  rather  than 
chemists. 

With  the  steam  process  for  obtaining  turpentine, 
the  services  of  a  chemist  are  not  so  essential 
unless  derivatives  are  to  be  made,  but  with  large 
destructive  distillation  plants,  one  chemist  or  sev- 
eral could  be  of  great  service  in  the  operation  of 
the  plant.  At  present  very  few  chemists  are  ac- 
quainted with  the  details  of  the  operation  of  wood 
distilling  plants  and  this  lack  of  familiarity  on 
their  part  has  been  pointed  out  to  their  disad- 
vantage, by  the  men  who  have  been  in  control  of 
these  plants.  But  put  an  experienced  chemist  in 
a  position  to  learn  the  details  of  the  business,  and 
his  general  knowledge  will  soon  place  him  far  in 
advance  of  the  men  engaged  in  the  business  who 
are  now  familiar  with  it.  This  superiority  has  been 
shown  markedly  in  other  lines  of  chemical  industry 
and  it  is  not  to  be  wondered  at,  as  this  is  what 
chemists  have  been  trained  for.  The  pine  wood 
distilling  business  is  not  attractive  to  chemists  as 
it  has  not  proved  to  be  a  very  paying  industry. 

The  following  scheme  of  chemical  control  is  not 
considered  to  be  anything  but  suggestive.  If  plants 
of  any  size  should  get  on  a  paying  basis,  and  a 
laboratory  established,  this  plan  could  be  modified 
to  suit  conditions  or  another  used  in  its  place.  The 
arrangement  naturally  falls  under  the  given  head- 
ings. 

Measurements. 

Wood. — This  should  be  weighed  in  the  car  or 
wagon  or,  if  desired,  measured,  but  weighing  is  to 


be  preferred.  When  sawdust  or  ground  wood  is 
used,  it  should  be  measured  by  the  capacity  of  the 
retorts  and  if  weight  is  desired,  the  approximate 
density  can  be  taken  by  sample.  The  trash  in  a 
load  should  be  weighed  once  in  a  while  to  deter- 
mine the  per  cent  in  this  form,  particularly  when 
long  wood  is  used. 

Crude  Turpentine. — This  should  be  weighed  also 
to  get  accurate  results,  but  for  technical  purposes 
it  can  be  measured  in  tanks  of  known  capacity, 
which  are  accurately  gauged.  When  sent  to  the 
still  the  temperature  should  be  taken,  the  specific 
gravity  and  a  sample  of  eacu  still. charge. 

Water  Separated  from  the  orude  Turpentine. — 
It  is  better  to  measure  this  through  a  meter,  the 
specific  gravity  and  temperature  being  taken  at 
suitable  intervals.  A  sample  should  be  taken  also 
so  as  to  be  able  to  determine  the  amount  of  oil 
that  may  escape. 

Caustic  Liquor. — This  should  be  kept  in  a  special 
air-tight  tank  of  known  capacity.  The  caustic 
should  be  weighed  and  the  water  measured  before 
mixing.  In  using,  the  strength  having  been  pre- 
viously determined  by  testing  a  sample,  the  tem- 
perature being  known,  the  quantity  of  liquor  used 
should  be  noted  by  the  gauge. 

Refined  Turps. — As  these  come  from  the  still,  the 
water  settling  out  can  be  measured  and  the  tem- 
perature taken.  A.  regular  sample  should  be  taken 
to  determine  any  loss  in  oil.  The  oils  can  be 
measured  from  each  run  in  the  separating  tanks 
when  barreled  or  when  pumped,  the  temperature 
being  taken. 

Condensing  Water. — The  water  from  each  con- 
denser can  be  measured  when  the  exact  working 
of  each  one  is  to  be  ascertained.  The  entire  con- 
densing water  used  may  be  measured  by  the  work 
of  the  pumps  or  by  sending  through  meters. 

Tarry  Products  and  Pyroligneous  Acid. — These 
products  from  the  retort  can  be  determined  by 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


149 


volume,  a  large  sample  being  taken  and  the  tem- 
perature noted.  This  should  be  done  before  any 
great  settling  takes  place.  The  workings  of  each 
separate  retort  should  be  gauged  as  far  as  pos- 
sible. 

After  settling,  if  acetate  is  to  be  made,  the  pyro- 
ligneous  acid  can  be  measured  and  sampled,  the 
temperature  taken  and  the  acid  sent  to  the  neu- 
tralized tank.  If  acetate  is  not  made,  the  acid 
should  be  sampled  and  sample  kept  to  test  the 
tar  content  and  the  acid  run  off.  The  tar  oil  can 
be  treated  similarly,  being  sure  in  all  cases  to 
note  the  temperature. 

Stills. — Measure  all  liquors  going  into  stills  and 
sample  same  and  take  temperature.  The  condensed 
water  and  condensing  water  should  be  measured 
as  used. 

Tar. — Should  be  weighed  when  barreled  or  when 
shipped  in  tank  cars.  At  other  times  measure  and 
sample,  noting  the  temperature. 

Other  Products. — The  same  general  rule  applies 
to  them.  Weigh  the  solids  and  measure  the  liq- 
uids, in  all  cases  sampling  and  noting  the  temper- 
ature. 

Sampling. 

Wood. — The  sampling  of  wood  is  a  very  difficult 
operation.  For  long  wood,  perhaps  the  best  way 
would  be  to  take  about  three  sticks  of  what  ap- 
peared to  be  average  wood  and  pass  them  through 
a  hog  and  thoroughly  mix  the  sample  thus  pro- 
duced.  It  should  be  quickly  covered  and  kept  in 
an  air-tight  vessel.  Hogged  wood  or  sawdust  can 
be  sampled  as  it  enters  the  retort. 

Crude  Turpentine. — In  bulk  a  sample  can  be  ob- 
tained by  simply  filling  a  suitable  bottle  and  cork- 
ing it.  To  sample  a  single  retort  which  is  not 
supplied  with  a  separate  receiver,  it  can  be  ar- 
ranged so  that  a  small  part  of  the  distillate  can 
flow  into  a  suitable  bottle.  A  sample  should  be 
taken  or  each  charge  entering  the  still. 

Other  Products. — All  the  other  liquid  products 
can  be  sampled  like  the  crude  turpentine. 

Liquors  in  Settling  Vats. — When  the  liquors  are 
of  such  a  nature  that  a  marked  separation  will 


not  take  place,  a  special  device  is  necessary  for 
sampling.  A  good  way  is  to  get  a  long  glass  tube 
about  one  inch  or  more  in  diameter  and  of  suf- 
ficient length  to  reach  the  bottom  of  the  tank.  One 
end  should  be  fitted  with  a  piece  of  rubber.  By 
inserting  this  tube  into  the  liquid  at  different 
levels,  a  number  of  samples  can  be  drawn  out  and 
collected  in  one  bottle  and  shaken  together. 

In  very  large  tanks  valves  can  be  placed  at  in- 
tervals on  the  tanks  and  the  samples  drawn  from 
each  and  mixed.  In  this  case,  it  is  necessary  to 
catch  a  large  sample  and  return  it  to  the  tank 
before  a  suitable  sample  can  be  obtained  from 
each  valve. 

Gas. — Samples  can  be  drawn  as  often  as  desired 
by  the  regular  methods.  The  flue  gases  should  be 
watched  in  starting  new  retorts  so  as  to  enable 
the  fireman  to  learn  their  peculiarities,  if  any. 

Standardizing    Apparatus. 

Balances  and  Weights.— Two  balances  should  be 
used,  one  sensitive  to  five  milligrams  and  the  other 
very  sensitive,  turning  when  loaded  with  one  or 
two-tenths  of  a  milligram. 

Test  the  balance  arms  by  balancing  weights 
against  each  other  and  then  changing  them  to 
the  opposite  pans,  where  they  should  again  balance 
each  other.  The  weights,  of  course,  should  be  stan~- 
ard  and  have  a  correct  relation  between  them  and 
the  balance  and  between  each  other. 

Polariscopes. — A  good  polariscope  should  be  used 
showing  left  and  right-handed  scales.  The  zero 
point  should  be  set  properly  and  all  errors  on  the 
scale  noted.  The  scale  can  be  checked  by  stand- 
ard quartz  plates,  and  these  latter  themselves 
checked  once  in  a  while. 

Refractometer. — This  instrument  as  well  as  the 
polariscope  should  be  standardized  at  20  degrees 
C.  Probably  for  technical  use  one  with  a  standard 
at  30  degrees  C.  would  be  better  on  account  of  the 
heat  in  summer.  Generally  a  form  similar  to 
Abbe's  would  be  suitable.  The  basis  used  is  dis- 
tilled water  with  its  reading  at  the  standardizing 
temperature. 

Thermometers. — These  should  be  compared  with 


150 


THE    UTILIZATION    OF    WOOD    WASTE,    BY    DISTILLATION. 


a  standard  thermometer  which  has  been  officially 
corrected. 

Hydrometers  or  other  form  of  spindles.  These 
can  be  checked  by  means  of  the  pycnometer. 

Flasks. — These  can  be  standardized  to  the  polar- 
iscope  temperature.  This  temperature  should  be 
used  for  everything.  By  marking  a  100  c.  c.  pi- 
pette so  as  it  will  deliver  exactly  100  c.  c.  at  the 
given  temperature,  all  the  flasks  can  be  standard- 
ized by  means  of  this.  Otherwise,  weigh  with  the 
proper  amount  of  water,  using  1  gram  in  vacuo  at 
4  degrees  C.  equal  to  1  c.  c. 

Water  Meters. — These  should  be  standardized  by 
weighing  a  quantity  of  water  passed  through. 

Tanks. — The  contents  of  these  can  be  most  ac- 
curately determined  by  filling  from  a  barrel  placed 
on  a  platform  scale,  weighing  all  water  admitted 
and  making  correction  for  temperature.  Other- 
wise, calculate  the  cubic  contents  from  measure- 
ments and  allow  for  the  temperature. 

Burettes  and  other  Volumetric  Apparatus. — The 
same  temperature  should  be  used  as  for  flasks  and 
contents  accurately  determined  by  weighing  the 
water  delivered.  When  one  piece  is  properly  stand- 
ardized it  can  be  used  to  standardize  the  others. 

ANALYSIS. 
Turpentine. 

For  the  analysis  of  turpentine  the  following 
method  is  given  by  the  Bureau  of  Supplies  and 
Accounts,  Navy  Department,  May,  1903. 

1.  The    turpentine    must   be    properly    prepared 
distillate  of  the  proper  kinds  of  pitch  or  pitch  pine, 
unmixed   with   any   other   substances;    it   must  be 
pure,  sweet,  clear  and  water  white. 

2.  A  single  drop  allowed  to  fall  on  white  paper 
must  completely  evaporate  at  a  temperature  of  70 
degrees  Fah.  without  leaving  a  stain. 

3.  The  specific  gravity  must  not  be  less  than 
0.862  or  greater  than  0.872  at  a  temperature  of  60 
degrees  Fah. 

4.  When  subjected  to  distillation,  not  less  than 
95  per  cent  of  the  liquid  should  pass  over  between 
the  temperatures  of  308  degrees  Fah.  and  330  de- 


grees Fah.,  and  the  residue  should  show  nothing 
but  the  heavier  ingredients  of  pure  spirits  of  tur- 
pentine. 

5.  A   definite   quantity   of   the   turpentine   is   to 
be  put  in  an  open  dish  to  evaporate,  and  the  tem- 
perature  of   the   dish    maintained    at   212    degrees 
Fah.;    if   a    residue    greater    than    2    per    cent    of 
the  quantity  remains  on  the  dish  it  will  constitute  a 
cause  for  rejection. 

6.  Flash   Tests. — An  open  tester  is  to  be  filled 
within  one-fourth  of  an  inch   of  its  rim  with  the 
turpentine,  which  may  be  drawn  at  will  from  any 
one  can  of  the  lot  offered  under  the  proposal.    The 
tester   thus    filled   will    be    floated    on   water    con- 
tained in  a  metal  receptacle.     The  temperature  ol 
the  water  will  be  gradually  and  steadily  raised  from 
its  normal  temperature  of  about  60   degrees  Fah. 
by  applying  a  gas  or  spirit  flame  under  the  recep- 
tacle;   the  temperature  of  the   water  is  to  be  in- 
creased at  the  uniform  rate  of  2  degrees  Fah.  per 
minute.     The  taper  should  consist  of  a  fine  linen 
or  cotton  twine  (which  burns  with  a  steady  flame) 
unsaturated  with  any  substance.     When  lighted  it 
is  to  be  used  at  every  increase  of  1  degree  tem- 
perature, beginning  at  100  degrees  Fah.     It  is  to 
be  drawn  horizontally  over  the  surface  of  the  tur- 
pentine and  on  a  level  with  the  rim  of  the  tester. 
The  temperature  will  be  determined  by  placing  a 
thermometer   in    the   turpentine   contained    in   the 
tester  so  that  the  bulb  will  be  wholly  immersed  in 
the  liquid.     The  turpentine  must  not  flash  below 
105  degrees  Fah. 

7.  Sulphuric  Acid  Test. — Into  a  30  cubic  centi- 
meter tube  graduated  to  tenths,  put  6   cubic  cen- 
timeters of  the  spirits  of  turpentine  to  be   exam- 
ined.    Hold  the  tube   under   the   spigot  and   then 
slowly  fill  it  nearly  to  the  top  of  the  graduation 
with  concentrated  oil  of  vitriol.     Allow  the  whole 
mass  to  become  cool  and  then  cork  the  tube  and 
mix  by  shaking  the  tube  well,  cooling  with  water 
during  the  operation,  if  necessary.     Set  the   tube 
vertical  and  allow  it  to  stand  at  the  ordinary  tem- 
perature of  the  room  not  less  than  half  an  hour. 
The  amount  of  clear  layer  above  the  mass  shows 
whether  the  material  passes  test  or  not.     If  more 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


151 


than  6  per  cent  of  the  material  remains  undis- 
solved  in  the  acid  this  will  constitute  cause  for 
rejection. 

A  test  of  turpentine  for  petroleum  oils  formerly 
used  was  to  agitate  the  oil  with  sulphuric  acid 
(two  parts  to  one  of  water)  then  distill  in  a  cur- 
rent of  steam.  Treat  the  distillate  of  oil  with  sul- 
phuric acid  (four  parts  acid  and  one  of  water)  and 
again  distill;  any  oil  coming  over  being  petroleum. 

The  chief  difference  between  wood  turpentine 
and  gum  turpentine,  as  now  produced,  is  in  the  dis- 
tillation test,  but  both  oils  vary  much  in  their 
properties.  Whether  it  is  advisable  to  adhere  to 
the  standard  set  for  orchard  turpentine  in  testing 
wood  turpentine  is  doubtful.  Perhaps  it  would  be 
advisable  to  make  a  new  standard  of  requirements 
for  wood  spirits  of  turpentine  and  make  all  manu- 
fac'urers  adhere  to  it. 

The  chief  concern  of  dealers  is  that  oil  of  tur- 
pentine contains  no  cheap  adulterations.  The  se- 
ries of  tests  given  above  will  locate  any  petroleum 
admixtures. 

Of  the  various  special  tests,  only  a  brief  outline 
will  be  herein  given.  Utz  observes  the  refractive 
index  and  treats  with  iodine  water  and  observes 
the  color  as  compared  with  a  known  sample  sim- 
ilarly treated.  H'ersfeld  treats  with  concentrated 
sulphuric  acid,  then  with  fuming  sulphuric  acid, 
only  a  small  definite  portion  of  oil  remains;  any 
excess  representing;  adulteration.  The  determina- 
tion of  the  refractive  index  is  made  on  small  frac- 
tions of  the  distilled  oil,  before  treatment  with  sul- 
phuric acid.  McCandless  makes  three  successive 
polymerizations  with  concentrated  sulphuric  acid 
once  and  fuming  acid  twice,  distilling  after  each 
treatment  in  a  current  of  steam  and  testing  the 
distilled  oil  in  the  refractometer.  Worstall  treats 
with  iodine  under  exact  conditions.  Hinsdale  evap- 
orates a  weighed  quantity  of  known  turpentine  in 
one  watch  glass  and  the  same  amount  of  unknown 
sample  in  another  and  places  them  in  a  water  bath 
at  170  degrees  Fah.  until  the  known  sample  evap- 
orates, the  residue  remaining  in  the  other  being 
adulterants.  Hall  treats  with  sulphuric  acid  under 
exact  conditions,  and  observes  the  rise  in  tempera- 


ture, similarly  to  the  Maumene  test  for  vegetable 
oils. 

Hydrochloric  acid  is  stated  to  turn  wood  turpen- 
tine black,  but  such  is  not  the  case  with  well- 
refined  samples. 

A  test  for  rosin  spirit  in  wood  turpentine  is  given 
by  Valenta  as  follows:  Mix  one  to  two  parts  of 
a  six  per  cent  solution  of  iodine  in  carbon  bisul- 
phide or  carbon  tetrachloride  and  heat  on  a  water 
bath.  A  green  to  olive  green  is  produced  by  pino- 
line  or  rosin  spirit  and  none  by  wood  spirit  or  tur- 
pentine. For  a  mixture  of  oil  of  turpentine,  wood 
turpentine  and  rosin  spirit  take  equal  volumes  of 
the  mixture  and  a  one  per  cent  solution  of  auric 
chloride  in  a  test  tube  and  shake,  heat  one  minute 
in  water  bath  and  shake  again.  Pure  oil  of  tur- 
pentine shows  separation  of  gold  in  oily  layer  only 
but  when  the  other  substances  are  present  the 
aqueous  solution  is  completely  decolorized. 

Wood  Oil. — No  satisfactory  tests  are  given  for 
this  oil,  as  it  is  of  such  a  varying  composition  as 
now  produced. 

At  those  plants  which  wish  to  make  a  standard 
certain  tests  might  be  applied.  These  would  have 
to  be  determined  by  the  chemist  in  charge  and  a 
standard  set. 

The  following  plan  might  be  of  service.  Test  for 
specific  gravity.  Take  the  iodine  value,  the  spe- 
cific rotary  power  and  refractive  index  (if  too  dark 
dissolve  in  water  white  petroleum),  take  the  flash 
test  and  fire  test,  determine  boiling  point,  try  tests 
given  under  turpentine,  and  for  creosote  oils,  de- 
termine the  amount  of  creosote  by  any  of  the  regu- 
lar methods.  From  these  data  a  definite  grade 
may  be  established  at  each  plant. 

A  method  of  investigation  to  determine  the  con- 
stitution of  wood  oil  is  to  be  found  in  the  Ameri- 
can Chemical  Journal,  Vol.  25,  No.  1.  This  cannot 
be  given  here,  as  it  cannot  very  well  be  carried 
out  in  a  technical  laboratory. 

Tar  Oil. — The  only  test  that  is  necessary  to 
make  on  this  oil  would  be  for  the  presence  of 
pyroligneous  acid.  It  has  been  found  that  the 
pyroligneous  acid  and  tar  do  not  always  separate 
distinctly  into  two  layers.  The  sample  of  the  mix- 


152 


THE    UTILIZATION    OP    WOOD    WASTE    BY    DISTILLATION. 


ture  is  taken  as  it  comes  over,  and  if  it  does  not 
separate  into  distinct  layers,  two  methods  may  be 
used  to  give  approximate  results  as  to  the  amount 
of  oil  and  acid  in  the  mixture. 

The  first  would  be  to  thoroughly  mix  the  sample 
and  then  take  out  a  definite  amount,  say  25  c.  c., 
put  in  a  graduating  cylinder  and  dilute  to  500  c.  c. 
(or  more,  according  to  the  rate  of  separation). 
When  thoroughly  separated  the  amount  of  tar  oil 
can  be  read  off  and  the  pyroligneous  acid  consid- 
ered to  be  the  difference  between  the  amount  of 
tar  oil  and  the  original  amount.  For  greater  ac- 
curacy the  bottom  part  of  the  graduated  cylinder 
could  be  made  of  small  bore  and  mounted  on  a  flat 
base. 

The  second  method  consists  in  placing  a  sample 
in  a  graduated  flask  of  a  centrifugal  tester,  and 
reading  the  percentage  of  tar  or  acid  from  the 
scale  after  revolving.  In  most  cases  a  special  flask 
would  need  be  used,  as  over  50  per  cent  of  the 
distillate  is  sometimes  acid;  the  centrifugal  tester, 
though,  would  be  the  best  device  to  use  for  the 
separation. 

In  taking  stock,  it  would  be  necessary  to  know 
the  amount  of  tar  in  the  tar  oil. 

To  do  this  a  sample  of  the  mixed  liquor  or  the 
tar  oil  itself  after  separating  the  acid,  should  be 
placed  in  a  distilling  flask  and  the  light  wood  oils 
distilled  by  means  of  a  current  of  steam.  The 
residual  tar  can  then  be  weighed  and  the  light 
oils  measured.  The  distillation  should  continue  no 
longer  than  the  degree  to  which  it  would  be  car- 
ried out  at  the  plant.  It  might  also  be  distilled 
with  water  and  the  light  oils  measured  and  the 
difference  considered  as  tar  or  the  tar  dried  and 
weighed. 

Measuring  the  oils  is  not  a  very  safe  way,  as 
they  are  soluble  in  water  to  a  considerable  extent. 

Tar. — When  the  tar  contains  water  a  quick  tech- 
nical way  would  be  to  separate  it  in  a  centrifugal 
tester  and  read  off  the  amount. 

One  test  for  tar  proper  has  already  been  given 
in  part.  It  consists  in  fractionally  distilling  the 
tar  in  a  distilling  flask  with  a  short  head.  Care 
should  be  used  at  first,  as  any  water  contained 


therein  causes  severe  bumping.  The  specifications 
are: 

Distilling  under  150  degrees  C.,        9.70  per  cent. 

Distilling  between  150-350  degrees,  42.61  per  cent. 

Distilling  between  350-363  degrees,  26.62  per  cent. 

Coke,  21.07  per  cent. 

Tar  varies  so  much  that  certain  definite  tests 
like  the  above  could  be  only  approximated.  The 
chief  methods  for  judging  tar  are  in  regard  to  the 
color,  weight  and  viscosity.  The  color  can  be  de- 
termined by  placing  a  drop  on  a  sheet  of  white 
paper;  the  spot  should  be  light  brown.  The  spe- 
cific gravity  varies  from  1.05  to  1.12.  The  thick- 
ness or  viscosity  is  generally  judged  by  the  eye. 
No  standard  can  be  set  for  this  property,  but  ar- 
rangements could  be  made  to  sell  tar  within  cer- 
tain limits  as  determined  by  a  viscosimeter.  An- 
other test,  to  distinguish  between  some  grades 
of  retort  tar  is  to  pour  a  drop  on  the  sur- 
face of  a  piece  of  smooth  white  poplar  or  deal 
wood  and  note  the  relative  length  of  time  it  takes 
for  the  sample  to  darken  on  exposure  to  the  air, 
as  compared  with  a  sample  of  known  quality. 

Acetates   and    Pyroligneous   Acid. 

To  determine  the  acid,  reckoned  as  acetic  acid, 
in  pyroligneous  acid,  several  methods  are  given. 
One  method  is  to  take  25  c.  c.  and  dilute  with 
1,000  c.  c.  or  more  of  distilled  water,  titrate  with 
normal  alkali,  using  phenolphthalein  as  an  indi- 
cator, and  calculate  the  percentage.  Often  with 
pine  wood  acid,  the  end  point  is  too  indistinct  and 
another  method  must  be  used. 

C.  Mohr  gives  the  following  method:  Weigh  off 
10  grams  of  wood  vinegar,  heat  in  a  beaker  with 
about  3  grams  of  pure  barium  carbonate  (test  the 
carbonate)  until  effervescence  ceases,  and  filter. 
The  solution  of  barium  acetate  is  strongly  colored, 
but  the  carbonate  remaining  undissolved  fvery 
little.  The  residue  after  washing  is  dried  and 
weighed  and  the  quantity  of  acetic  acid  present 
calculated;  each  gram  of  dissolved  carbonate  cor- 
responding to  0.809  gram  of  acetic  acid  or  10 
grams  of  wood  vinegar  contains  6.09  per  cent. 

It  is  quicker  to  treat  the  undissolved  carbonate 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


153 


with  an  excess  of  normal  nitric  acid  and  titrate 
back  with  normal  soda,  using  litmus  as  an  indica- 
tor. 

Instead  of  barium  carbonate,  Mohr  also  uses 
precipitated  moist  calcium  carbonate,  the  alkalin- 
ity of  which  is  determined.  This  is  added  to  the 
wood  acid  in  excess  and  the  mixture  boiled  to  ex- 
pel C  Oz,  then  filtered  and  treated  as  before. 

Acetates. 

Acetate  of  lime,  such  as  the  brown  and  gray, 
are  tested  for  acetic  acid  in  various  ways.  Two 
methods  will  be  given. 

Stillwell  and  Cladding's  method  is  as  follows: 

A  100  to  120  c.  c.  retort,  the  tubulure  of  which 
carries  a  small  funnel  fitted  in  with  a  rubber  stop- 
per, and  the  neck  of  the  funnel  stopped  tightly 
with  a  glass  rod  shod  with  elastic  tube,  is  sup- 
ported upon  a  stand  in  such  a  way  that  its  neck 
(the  retort  neck)  inclines  upwards  at  about  45 
degrees;  the  end  of  the  neck  is  drawn  out  and 
bent  so  as  to  fit  into  the  condenser  by  help  of  an 
elastic  tube.  The  greater  part  of  the  retort  neck 
is  coated  with  flannel,  so  as  to  prevent  too  much 
condensation. 

One  gram  of  the  sample  being  placed  in  the  re- 
tort, 10  c.  c.  of  a  40  per  cent  solution  of  Pz  Os 
are  added,  together  with  as  much  water  as  will 
make  about  50  c.  c.  A  small  naked  flame  is  used 
and  if  carefully  manipulated,  the  distillation  may 
be  carried  on  to  near  dryness  without  endangering 
the  retort.  After  the  first  operation  the  retort 
is  allowed  to  cool  somewhat,  then  50  c.  c.  of  hot 
water  added  through  the  funnel,  another  distilla- 
tion made  as  before,  and  the  same  repeated  a  third 
time,  which  will  suffice  to  carry  over  all  the  acetic 
acid.  The  distillate  is  then  titrated  with  alkali 
and  phenolphthalein. 

The  following  is  the  method  of  Grimshaw,  taken 
from  Allen's  Organic  Analysis,  as  given  by  Sutton: 

Method  of  Procedure:  10  grams  of  the  sample 
are  treated  with  water  and  an  excess  of  sodium 
bisulphate  (Na  H  SO<)  the  mixture  diluted  to 
definite  volume,  filtered  and  a  measured  portion 
of  the  filtrate  titrated  with  standard  alkali;  a  sim- 


ilar portion  meanwhile  is  evaporated  to  dryness 
with  repeated  moistenings  with  water,  to  drive  off 
all  free  acetic  acid.  The  residue  is  dissolved  and 
titrated  with  standard  alkali,  when  the  difference 
between  the  volume  now  required  and  that  used 
in  the  original  solution  will  correspond  to  the 
acetic  acid  in  the  sample.  Litmus  paper  is  the 
proper  indicator. 

Wood. 

The  only  tests  necessary  to  be  made  on  wood 
are  those  which  determine  its  content  of  water 
and  resin. 

Sampling  is  the  most  difficult  part.  If  possible, 
a  few  average  sticks  from  a  cord  lot  should  be 
passed  through  a  suitable  disintegrating  machine. 
In  the  absence  of  this,  each  stick  should  be  cut 
into  in  several  places,  and  rasped  a  little  at  each 
place,  with  a  wood  rasp.  In  both  cases  the  finely 
divided  product  should  be  bottled,  so  as  to  pre- 
vent the  evaporation  of  moisture. 

Moisture. 

Determine  this  by  heating  a  sample  of  two 
grams  or  more  in  an  air  bath  kept  at  105-110  de- 
grees C.  Cool  in  a  desiccator  and  weigh  and  the 
loss  in  weight  indicates  thei  moisture.  This  method 
is  not  so  very  accurate,  as  the  wood  is  ant  to 
oxidize  slightly,  and  in  fat  woods  a  great  deal 
of  turpentine  would  escape  with  the  water. 

The  author  knows  of  no  method  for  testing  this 
class  of  wood,  but  would  suggest  the  following: 

Take  2  to  5  grs.  of  the  finely  divided  wood  and 
place  in  a  weighing  bottle  fitted  with  a  tight 
ground  glass  stopper.  Make  a  hole  in  the  stopper 
and  weld  a  piece  of  glass  tubing  around  the  open- 
ing, then  bend  the  tubing  so  as  to  form  a  U.  In 
the  tube,  put  pieces  of  lime  or  soda  lime.  Weigh 
the  stopper  and  the  tube  containing  the  lime,  also 
weigh  the  bottle  and  its  contents.  Insert  the 
stopper  in  the  weighing  bottle  and  place  the 
whole  apparatus  in  an  oven  heated  to  about  105- 
110  degrees  C.  Heat  for  one  hour,  then  with- 
draw the  apparatus  and  allow  to  cool  either  in  a 
desiccator  or  by  closing  the  end  of  the  U  tube. 


154 


THE    UTILIZATION    OF    WOOD    WASTE    BY   DISTILLATION. 


Weigh  each  part  separately.  Repeat  until  the  loss 
in  weight  of  the  weighing  bottle  is  relatively  con- 
stant. Then  heat  the  tube  containing  the  lime 
to  about  200  degrees  C.  in  an  air  bath  or  other- 
wise; cool  and  weigh,  repeating  until  the  loss  in 
weight  is  constant. 

The  method  is  based  on  the  following  apparent 
principles:  The  first  heating  drives  the  water 
and  any  oil  over  into  the  tube.  The  lime  fixes  the 
water.  Any  oil  condensed  is  driven  off  by  the  sec- 
ond heating.  Slaked  lime  holds  its  water  of  com- 
bination even  when  heated  to  250  to  300  degrees  C. 

The  loss  in  weight  of  the  weighing  bottle  rep- 
resents moisture  plus  volatile  oil.  The  weight  of 
the  lime  tube  after  the  second  heating  minus  its 
original  weight  represents  the  moisture.  The  moist- 
ure found  subtracted  from  the  moisture  and  oil 
lost  from  the  weighing  gives  the  amount  of  vola- 
tile oil.  If  any  volatile  oil  is  found  to  have  passed 
over,  it  should  be  considered  as  turpentine  and 
added  to  the  amount  found  by  distilling  the  ether 
extract. 

A  method  used  in  determining  moisture  in  ex- 
plosives containing  volatile  oils  might  also  be 
used.  It  consists  in  treating  the  ground  sample 
with  calcium  carbide  in  a  tube,  taking  precaution 
not  to  mix  the  two  until  the  tube  is  connected 
with  a  gas  measuring  apparatus.  The  acetylene 
gas  formed  is  measured  over  salt  water  and  cor- 
rections made  for  temperature  and  pressure.  An 
allowance  is  also  to  be  made  for  the  amount  of 
moisture  retained  by  the  lime  formed  during  the 
reaction,  as  this  moisture  does  not  act  on  the  cal- 
cium carbide.  On  this  account  1  c.  c.  acetylene 
equals  .001725  gr.  moisture,  instead  of  .00162  gr. 

In  making  the  test  the  reaction  can  be  hastened 
by  heating  in  a  water  bath  to  100  degrees  C. 

The  wood  residue  from  the  moisture  determina- 
tion is  placed  in  a  filter  cone  of  a  Soxhlet  fat  ex- 
traction apparatus  and  the  cone  inserted  in  the 
tube.  The  tube  should  then  be  connected  with 
the  flask.  It  will  be  found  that  in  determining  the 
moisture  of  fat  wood  that  some  of  the  resin  has 
exuded  from  the  wood  on  account  of  the  heat  and 
flowed  to  the  bottom  of  the  crucible  or  other  con- 


tainer used  in  making  the  determination.  After 
removing  the  wood  this  resin  can  be  dissolved  in 
ether  and  poured  upon  the  cone  in  the  tube.  The 
apparatus  is  used  as  in  making  an  ordinary  fat 
analysis,  the  resin  being  extracted  from  the  wood 
and  collected  in  a  small  flask.  The  ether  is  evap- 
orated and  the  flask  cooled  and  weighed.  The  dif- 
ference between  this  weight  and  the  weight  of  the 
empty  flask  equals  the  weight  of  the  extracted 
matter.  By  connecting  the  flask  with  a  suitable 
condenser  and  carefuly  heating  it,  the  turpentine 
will  distill  over.  It  is  better,  though,  to  make  this 
distillation  by  simply  passing  a  current  of  steam 
through  the  extracted  resin,  and  the  turpentine 
will  distil  without  danger  of  decomposition  of  the 
resin. 

The  turpentine  can  be  separated  from  the  water 
and  weighed  or  measured.  The  flask  containing 
the  resin  should  then  be  placed  in  an  air  bath 
until  the  water  is  driven  off,  and  then  weighed. 
The  difference  between  this  weight  and  the  weight 
of  the  flask  equals  the  weight  of  resin.  The  weight 
also  serves  as  a  check  on  the  turpentine. 

The  woody  fiber  left,  after  extracting  with  ether 
can  be  burned  in  a  crucible  and  the  residue 
weighed  as  ash.  If  desired  it  can  be  distilled  by 
placing  it  in  a  glass  retort.  The  retort  should 
be  placed  in  an  air  bath,  the  tube  of  the  retort  ex- 
tending through  an  opening  in  the  side  and  con- 
necting with  a  condenser.  The  condensed  products 
can  then  be  collected  and  separated  and  each 
weighed  separately.  The  charcoal  should  also  be 
weighed.  The  gas  can  be  collected  and  measured. 

The  acetic  acid  in  the  pyroligneous  acid  can  be 
determined  by  Mohr's  method  and  the  wood  alco- 
hol by  the  phosphorous  diiodide  method,  given  un- 
der pyroligneous  acid  and  wood  alcohol,  respec- 
tively. 

Determination  of  real  methyl  alcohol  in  wood 
spirit  (Allen's  Org.  Analysis,  Vol.  1,  p.  73). 

A  dry  flask  is  furnished  with  a  cork  fitted  with 
a  tapped  funnel  or  pipette  and  connected  with  an 
inverted  condenser;  15  grams  of  phosphorous  diio- 
dide are  placed  in  the  flask  and  5  c.  c.  qf  the  sam- 
ple of  wood  spirit  (measured  at  15  degrees  C.)  add- 


THH    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


155 


ed  slowly,  drop  by  drop,  by  means  of  a  pipette;  5 
c.  c.  measure  hydriodic  acid  of  1.7  sp.  gr.  con- 
taining in  solution  8.5  grams  of  free  iodine  is  next 
added  through  the  pipette.  The  flask  is  then 
heated  to  80  to  90  degrees  C.  by  immersion  in  hot 
water  for  a  few  minutes,  after  which  the  condenser 
is  placed  in  the  ordinary  position  and  the  contents 
of  the  flask  are  distilled  and  collected  in  a  grad- 
uated tube.  The  distillate  is  shaken  wiLh  water 
and  the  volume  of  methyl  iodide  read  off.  Correc- 
tions of  8  volumes  per  1,000  must  be  made  for 
the  solubility  of  the  methyl  iodide  in  water,  and 
for  the  loss  due  to  the  vapor  which  fills  the  ap- 
paratus. This  error,  which  is  constant  for  the 
same  apparatus,  is  determined  by  distilling  a 
known  measure  of  iodide  of  methyl,  measuring  the 
distillate  and  thus  ascertaining  the  loss.  Krell 
prefers  to  pass  a  current  of  air  into  the  apparatus, 
through  the  pipette,  and  thus  drive  out  the  vapor 
of  methyl  iodide.  Under  these  conditions,  5  c.  c. 
of  pure  anhydrous  methyl  alcohol  yields  7.45  c.  c. 
of  the  iodide. 

By  the  iodine  process  any  methyl  acetate  pres- 
ent in  the  sample  is  converted  into  iodide  and 
hence  increases  the  apparent  percentage  of  methyl 
alcohol.  For  most  purposes  the  error  thus  intro- 
duced can  be  neglected.  If  desired  the  quantity 
present  can  be  previously  determined  approximate- 
ly by  heating  a  known  quantity  of  the  wood  spirit 
with  standard  soda  and  titrating  the  excess  with 
standard  acid.  Forty  parts  of  Na  O  H  neutralized 
corresponds  to  74  of  methyl  of  acetate,  or  32  of 
methyl  alcohol.  The  amount  of  methyl  alcohol  so 
found  should  be  subtracted  from  the  total  amount 
corresponding  to  the  iodide  in  order  to  ascertain 
the  real  amount  of  methyl  alcohol  existing  as  such 
in  the  sample. 

When  acetone  is  present  it  distills  over  with 
the  methyl  iodide,  and  it  is  only  by  repeated  wash- 
ing that  the  distillate  can  be  wholly  freed  from  it. 
Bardy  and  Bordet  have  constructed  a  table  showing 
the  diminution  in  volume  undergone  by  methyl 
iodide  containing  various  percentages  of  acetone  by 
washing  with  water.  In  the  absence  of  the  table, 
the  error  caused  by  the  presence  of  acetone  might 


be  avoided  by  saponifying  the  washed  distillate 
with  alcoholic  potash  evaporating  to  dryness,  dis- 
solving the  residue  in  water,  acidulating  an  aliquot 
part  of  the  solution  with  nitric  acid,  and  then  pre- 
cipitating the  iodide  by  silver  nitrate.  235  parts 
of  iodide  of  silver  represent  32  of  methyl  alcohol. 

Dimethyl  acetal  also  comes  over,  5  c.  c.  of  which 
yield  5.3  c  c..  of  methyl  iodide.  The  others  are 
either  soluble  in  water  or  are  converted  into  resin- 
ous bodies. 

For  the  preparation  of  the  iodide  of  phosphorous, 
15.5  grm.  of  phosphorous  are  dissolved  in  350  c.  c. 
of  carbon  disulphide,  and  127  grm.  of  iodine  are 
gradually  added,  the  vessel  being  kept  well  cooled. 
The  diiodide  separates  in  crystals,  which  are  dried 
in  a  slightly  warm  current  of  air  and  preserved 
in  a  well-stoppered  bottle.  A  qualitative  test  for 
methyl  alcohol  given  by  Mulliken  &  Scudder  con- 
sists in  plunging  a.  hot  copper  spiral  into  the  liquid 
to  be  examined  and  adding  one  drop  of  a  solution 
of  one  part  resorcin  in  200  parts  of  water,  then 
pour  the  solution  carefully  upon  concentrated  sul- 
phuric acid  so  as  not  to  mix.  After  three  min- 
utes with  slight  mixing  methyl  alcohol  causes  rose 
red  flocks. 

Creosote. — There  are  many  substances  that  go  by 
the  name  of  creosote.  Coal  tar  creosote  and  wood 
tar  creosote  are  separated  by  Hagar's  method.  The 
following  is  an  abstract  of  Allen's  description  of 
Hagar's  method: 

Three  measures  of  absolute  glycerol  are  mixed 
with  one  measure  of  water,  and  the  solution  used 
as  a  solvent.  Treat  one  measure  of  the  sample  in 
a  Mohr  burette  with  three  measures  of  the  diluted 
glycerol,  and  allow  the  liquid  to  stand  until  sep- 
aration has  occurred.  If  the  creosote  be  pure,  the 
volume  will  remain  unchanged.  If  reduced  the  gly- 
cerol layer  is  tapped  off  and  the  remaining  creo- 
sote again  shaken  with  three  times  its  measure 
of  diluted  glycerol  and  the  measure  again  observed, 
This  second  treatment  will  always  suffice  for  the 
removal  of  the  coal  tar  acids,  unless  their  propor- 
tion is  very  large,  and  hence  the  volume  of  the 
residual  layer  will  indicate  the  proportion  of  real 
wood  creosote  in  the  quality  of  sample  taken.  The 


156 


THE    UTILIZATION    OF    WOOD    WASTE    BY    DISTILLATION. 


nature  of  the  residual  creosote  can  be  verified  by 
the  collodion  test  (should  form  a  clear  solution) 
while  the  coal  tar  acids  can  be  recovered  from  the 
glycerol  solution  by  filtering  it  to  remove  suspend- 
ed traces  of  wood  creosote,  diluting  with  water 
and  agitating  with  chloroform.  On  spontaneous 
evaporation  of  the  separated  chloroform  the  coal 
tar  acids  are  obtained  in  a  condition  of  sufficient 
purity  to  allow  of  their  positive  recognition. 

Acetone. — The  gravimetric  determination  of  this 
substance  is  by  means  of  caustic  and  iodine.  A 
volumetric  method  that  can  be.  used  in  presence 
of  ethyl  alcohol  is  given  by  Sutton,  as  follows, 
modified  by  Squibb  and  Kebler.  The  solutions  re- 
quired are  as  follows: 

(1)  A  6  per  cent  solution  of  hydrochloric  acid. 

(2)  A  decinomal    solution     of     sodium   thiosul- 
phate. 

(3)  Alkaline  potassium  iodide  solution  prepared 
by  dissolving  250  gm.  of  potassium,  257  gm.  of  so- 
dium   hydroxide   (by    alcohol)    in,    water,    likewise 
made  up  to  a  litre.     After  allowing  the  latter  to 
stand,  800  c.  c.  of  the  clear  solution  are  added  to 
the  liter  of  potassium  iodide. 

(4)  Sodium  hypochlorite  solution:      100  gm.   of 
bleaching  powder,  (35  per  cent)  are  mixed  with  400 
c.  c.  of  water;   to  this  is  added  a  hot  solution  of 
120  gm.  of  crystalized  sodium  carbonate  in  400  c.  c. 
of  water.    After  cooling,  the  clear  liquor  is  decant- 
ed, the  remainder  filtered  and  the  filtrate  made  up 
to  a  litre;  to  each  litre  is  added  26  c.  c.  of  sodium 
hydroxide  solution  (sp.  gr.  1.29). 

(5)  An  aqueous  acetone  solution  containing  1  or 
2  per  cent  of  acetone  as  pure  as  may  be  had,  say, 
99.7  per  cent. 

(6)  Starch  solution,  prepared  by  treating  0.125 
gr.  of  starch  with  5  c.  c.  of  cold  water,  then  adding 
20   c.   c.   of  boiling  water,  boiling  a   few   minutes, 
cooling  and   adding  2  gm.  of  sodium  bicarbonate. 
This  starch  solution  will  keep  for  some  weeks. 

To  20  c.  c.  of  the  potassium  iodide  solution  are 


added  10  c.  c.  of  the  diluted  aqueous  acetone,  an 
excess  of  the  sodium  hypochlorite  solution  is  then 
run  in  from  a  burette  and  well  shaken  for  a  minute. 
The  mixture  is  then  acidified  with  the  hydro- 
chloric acid  solution,  and  while  agitated  an  excess 
of  sodium  thiosulphate  solution  is  run  in  the  mix- 
ture, being  afterwards  allowed  to  stand  a  few 
minutes.  The  starch  indicator  is  then  added  and 
the  excess  of  thiosulphate  retitrated.  The  relation 
of  the  sodium  hypochlorite  solution  to  the  sodium 
thiosulphate  being  known,  the  percentage  of  ace- 
tone can  be  readily  calculated. 

In  the  above  reaction  1  molecule  of  acetone  re- 
quires 3  mol.  of  iodine  to  four  1  mol.  of  iodoform. 
One  atom  of  available  chlorine  will  liberate  one 
atom  of  iodine  from  the  K  I  in  the  alkaline  solu- 
tion, or  1  c.  c.  will  liberate  just  enough  I  to  make 
1  c.  c.  of  the  same  normal  strength  as  the  hypo- 
chlorite solution  originally  was;  therefore,  by  read- 
ing the  number  of  c.  c.  of  hypochlorite  consumed 
as  so  many  c.  c.  of  iodine  solution  of  the  same 
normal  strength,  the  calculation  is  reduced  to  the 
basis  of  iodine.  Expressing  it  as  a  proportion  and 
letting  y  equal  the  amount  of  combined  I  and  x 
that  of  acetone,  we  have  (taking  I  as  126.5) 

58 
759:58:  :y:x  or  x=y  759  or  x=y  0.07641. 

Example  of  calculation — 10  c.  c.  of  the  acetone 
solution  containing  1  gm.  of  the  liquid  to  be  anal- 
yzed required  14.57  c.  c.  of  iodine  solution  of  same 
strength,  or  combining  we  have 

14.57x0.806x0.1260x.Q7641 

1  gm  of  solution  of  acetone"11'351  per  cent 

Many  other  methods  of  analysis  of  the  various 
products  should  be  reviewed  in  order  to  get  a  sys- 
tematic routine  for  a  wood  distilling  plant.  Of 
the  methods  given,  all  are  recognized  as  standards 
for  the  particular  conditions  and  products  to  which 
they  apply.  It  is  beyond  the  scope  of  this  work 
to  give  more  methods  than  are  herein  contained. 


CORRECTIONS  AND  ADDENDA 


Table  of  Contents,  Page   118,  instead  of  Steam  Plant,   It  should  be  Estimates. 

Illustrations,    Fig.   45   should  be   Sibbet  &    McLean's  Process  and   Fig.    53  Copilovich 
Process,    Page   80. 

Page     81,  first        column,   15th  line,  shaped   should    be   shape. 

Page     32,  first        column,  2nd  line,   small   should   be  light. 

Page     33,  first        column.  2nd  line,     omit    "or   the  retort   cool   off   suddenly." 

Page  33,  second  column,  3()th  line,  after  "condensed,"  to  be  more  accurate  it 
should  have  been  stated  that  in  a  large  pipe  a  'slower 
motion  would  take  place,  thus  allowing  more  time  for 
the  vapors  to  come  in  contact  with  the  walls. 

Page  39,  first        column,  29th  line,    I    should    be    It. 

Page  39,  first        column,  37th  line,    3    should    be    5. 

Page  44,  first        column,  22nd  line,    sifter    "and   the"    add    entering. 

Page  47,  first        column.     3rd  line,    P    should    be    D. 

Page  47,  first  ,   column,  22nd  line,    omit   all    to   25th    line. 

Page,  91,  Credit  should  be  given  Jackson  for  the  ready  means  of  discharge  in 
his  apparatus. 

Page    03,  first       column,  1st  line,  c  is   the  opening  above  grate. 

Page     83,  second  column,  3rd  line,   "of"    should    be    to    find. 

Page  105,  second  column,  5th  line,  pyroligenous    should    be    pyroligneous. 

Page  117,  first        column,  5th  line,  collects    should    be    collect. 

Page  122,  first        column,  13th  line,  methylfurfural    should    be    methylfurfurane. 

Page  128,  second  column,  30th  line,  after    "rosin"    put    oil. 

Page  143,  first  column,  6th  line,  in  table  should  read  coke  600  to  700  pounds, 
not  gallons. 

Page  144,  first       column,  14th  line,  after    "potassium"    add    salts. 

Page  144,  second  column,  3rd  line  from  bottom,  the  second  sawdust  should  be  alcohol. 

Page  145,  first        column,  5th  line,   "sulphuric"    should    be    sulphur. 

Page  152,  second  column,  42nd  line,  omit  "10  grains  of  wood  vinegar  contains  6.0!> 
per  cent.'' 

Page  156,  first       column,  17th  line,  "decinomal"    should   be    decinormal. 

Page  156,  first  column,  20th  line,  after  "potassium"  read  in  a  litre  of  distilled 
water. 

Page  156,  second  column,  14th  line,  "four"  should  be  form. 


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